1996 TxPORT, All rights reserved. No part of this publication may be reproduced, transmitted, transcribed , stored in a
retrieval system, or translated into any language in any form by any means without the written permission of TxPORT.
Reorder # 34-00255
st
1
Edition, August 1996
TxPORT shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material. TxPORT reserves the right to revise this publication from time to time and make
changes in content without obligation to notify any person of such revision changes.
Contents of this publication may be prelimin ary and/or may be ch anged at any time with out notice and s hall not be regarded
as a warranty.
Documentation Disclaimer
TxPORT makes no representation or warranties of any kind whatsoever with respect to the contents hereof and specifically
disclaims any implied warranties of merchantability or fitness for any particular purpose.
The TxPORT 1558D APS CSU/DSU (Automatic Protection
Switch with integral V.35 DSU/CSU) provides the ideal
solution for mission-critical high speed data applications
requiring redundant path T1 access. The 1558D supports
both T1 and FT1 high speed applications and can automatically restore your applicat ion when a problem arises on
either the primary or standby T1 facility. See the ‘Operation’
chapter for a typical APS application. Switching from the
failed T1 line (Path A or Path B) to the standby (Path A or
Path B) is based upon user definable switching alarm thresholds (errored seconds, consecutively severely errored seconds, loss of signal, loss of frame). The 1558D APS CSU/
DSU is fully compatible with AT&T 54017 T1 protection
standards, AT&T 54016 ESF performance standards and TR
62411 T1 standards.
Features
The APS CSU/DSU unit is designed s o that it can be configured to support a wide variety of user applications and
speeds. The key features and functions are:
• Mission-Critical Automatic Protection Switching from a Fail
or Impaired T1 F acili ty to a St an dby T1 F a cili ty
• AMI or B8ZS Line Coding
• Integral ESF CSUs (TR 54016 compl iant)
• 24 Hour Performance History
• Revertiv e and Non-rev erti v e Operation
• User-Definable Alarm Switching Thresholds
Specifications
T1 Network Interface
Line Rate:1.544 Mbps
Framing:ESF
Line Code:AMI or B8ZS
DS1 Interface:+1 to -27 dB ALBO, 100 Ω (± 5%)
Connector:RJ-48 modular jack
Overvoltage Primary and Secondary lightning
Protection:fusing for line cross
V.35 CPE (Equipment Interface)
Standards:Complies with CCITT V.35
Data Rates:56Kb to 1.536 Mbps (n x 56/64)
Clocking:Internal, External, Network
Looping:Local and Remo te (per V.54)
Data Invert:Enable/Disable
Connector:Female, 34-pin
Diagnostics
Line Loop:Signal regeneration only (bidirectional)
Payload Loop:Signal regenerated with new frame syn-
chronization, CRC6, and data.
Loop ActivationIndustry standard formats and De-acti-
with 19” rack mount hardware)
Dimensions:17.25" W, 1.75" H, 12" D
Weight:5 lbs.
Environmental
Operating Temp:0° to 50° C(32° to 122°F)
Storage Temp:-20° to 85° C(-4° to 185°F)
Humidity:95% maximum (non-condensing)
Compatibility
PUB 54017:Automatic Protection Switching Equip-
ment, 1991
TR 62411:T1 interface and CSU specifications
PUB 54016:ESF requirements
CCITT:V.35
Industry Listings
FCC Compliance: Part 15 Subpart B, Clas s A
FCC Part 68 Registration:
UL Listed:
CSA Certified:
IC/CS03:
FCC Requirements
This equipment has been tested and found to comply with
the limits for a Class A digital device, pursuant to Part 15 of
FCC Rules. These limits are designed to provide reasonable
protection against harmful interference when the equipment
is operated in a commercial environment. This equipment
generates, uses, and can radiate radio frequency energy and
if not installed and used in accordance with the instruction
manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is
likely to cause harmful interference in which case the user is
required to correct the interference at his own expense.
Shielded cables must be used to ensure compliance with
the Class A FCC limits.
Modifications to this unit not
expressly approved by the party
responsible for compliance could void the
user ’s authority to operate the equipment.
This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions:
1. This device may not cause harmful interference.
2. This device must accept any interference received,
including interference that may cause undesired operation.
Notice to Users of 1.544 Mb/s Service:
instructions are provided to ensure compliance with FCC
Rules, Part 68:
1. All direct connections to T1 lines must be made using
standard plugs and jacks.
2. The following information may be required by the local
telephone company when applying for leased line facilities:
Table 1-A. Leased Line Information
Port ID REN / SOC FIC USOC
P/N/12 - 00635 6.0 N 04DU9-BN
04DU9-DN
04DU9-IKN
04DU9-ISN
3. If the unit appears to be mal functioning , it should be disconnected from the telephone lines until you learn
whether the source of trouble is your equipment or the
telephone line. If your equipment needs repair, it should
not be reconnected until it is repaired.
4. The unit has been designed to prevent harm to the T1
network. If the telephone company finds that the equipment is exceeding tolerable parameters, they can temporarily disconnect service. In this case, the telephone
company will give you advance notice, if possible.
5. Under FCC rul es, no cus tomer is autho rized to repair thi s
equipment. This restriction applies regardless of whether
the equipment is in or out of warranty.
6. If the telephone company alters their equipment in a
manner that will affect the use of this device, they must
give you advance warning so that you can have the
opportunity for uninterrupted service. You will be
advised of your right to file a complaint with the FCC .
7. The attached affidavit must be completed by the installer.
8. In the event of equipment malfunction , all repairs sh ould
be performed by our company or an authorized agent. It
is the responsibility of users requiring service to report
the need for service to our company or to one of our
authorized agents.
The following
RJ-48C
Canadian Emissions
Requirements
This digital apparatus does not exceed the Class A limits for
radio noise emissions from digital apparatus set out in the
Radio Interference Regulations of the Canadian Department
of Communications.
General 1-2
1558D APS CSU/DSU
End users should use existing 48 VDC battery
sources or a CSA certified power supply.
Le present appareil numerique n’emet pas de bruits radioelectriques depassant les limites applicables aux appareils
numeriques (de la class A) prescrites dans le Reglement sur
le brouillage radioelectrique edicte par le ministere des
Communications du Canada.
• One PC to 1558D user interface cable
• AC Pow er Cord
• T wo 10' RJ-48 modular T1 cables
The following is a list of the standard and optional equipment which may also be needed.
Table 1-B. Available Equipment and Part Numbers
Warranty
TxPORT warrants each unit against defects in material and
workmanship for a period of five years from the date the
unit was shipped to the customer. If the unit malfunctions at
any time during the warranty period, TxPORT will repair, or
at TxPORT’s option, replace the unit free of charge.
The remedies listed herein are the users sole and exclusive
remedies. TxPORT shall not be liable for any indirect,
direct, incidental or consequential damages. The owner must
return the unit to the factory, shipping prepaid and packaged
to the best commercial standard for electronic equipment.
TxPORT will pay shipping charges for delivery on return.
The customer is responsible for mode and cost of shipment
to TxPORT. This warranty does not apply if the unit has
been damaged by accident, misuse or as a result of service
or modification by other than TxPORT personnel.
When returning the unit for warranty work, a Return Material Authorization (RMA) number must be obtained from
customer service at the address/ phone number given at the
end of this chapter. When calling TxPORT to obtain a
Return Material Authorization number or to arrange service,
please have the following information available:
• Model number(s) and serial number(s) for the unit(s).
• Reason for return and symptoms of problem.
• Warranty status (if known).
• Purchase order number to cover charges for out-of-warranty
items.
• Name and phone number of person we can contact if we
have questions about the unit(s).
• Mode of shipment required (second day air is the normal
mode of shipment for all returned material unless otherwise
specified).
As soon as TxPORT has the above information, the RMA
that must accompany the item(s) returned can be issued.
Ordering Numbers
The 1558D is shipped from the factory with the following
standard items:
• The 1558D reference manual
• 19" rack mount hardware
• Local Access PC software
Part NumberEquipment
F-1558-001D-1111
6-3030-035-1
6-3030-036-1
9-1558D-003-1PC DOS Local Access software on 3.5”
9-1001-029-2
9-1001-004-0 10
1558D unit with integral ESF CSUs
and V.35 DSU, 110 VAC operation.
19" Rack Mount Hardware for
1558D. Standard with 1558D unit.
23" Rack Mount Hardware for
1558D. Ordered as an option to the
1558D.
Disk. Allows the user to access unit performance, status, and configurati on
information and to perform loca l loo p
testing.
PC to 1558D data cable, 10' DB-9 to
6-pin modular. Standard with 1558D
unit.
RJ-48 8-pi n modular 10' c able Contact the factory for additional cable
lengths and types.
TxPORT Customer Service
Address: TxPORT
127 Jetplex Circle
Madison, Alabama 35758
Telephone: 888-4TxPORT
800-926-0085 or
205-772-3770
Customer Service Returns: 800-926-0085, ext. 2227
Product Technical Support
Normal Hours - 8 a.m. to 5 p.m. Central, Monday – Friday
Proper installation of the 1558D unit involves the following
key steps:
• Site Survey and Preparation
• Unpacking and Inspecting Equipment
• Equipment Mounting
• T1, Alarm, and Power Connections
• Setting Equipment Options
• Preservice Testing
The following paragraphs contain information and instructions to assist the user in preparing the 1558D for operation.
A tear-out configuration guide (P/N 45-00083) is included
in the back of this manual. It is recommended that the user
sequentially follow the site preparation and unit installation
steps described.
Site Preparations
The following site preparations should be performed before
starting installation of the 1 558D A PS C SU/ DSU un it. F irst,
determine the physical location of 1558D unit and perform
the following:
1. Determine the distance from the APS unit to the AC
power outlet. The 1558D is shipped from the factory
with a industry standard 3-prong, 5.5 ft. AC power cord.
The maximum current draw of the 1558D is ≤75 milliamps.
2. Determine t he distance from the T1 facility demark and
the actual location of the 1558D. After determining distance, verify that the proper cable lengths and types have
been ordered to connect from the T1 demark to the
1558D unit. The 1558D is shipped with three RJ-48
modular T1 cable, 10 feet in length.
3. Normally, the provider of the T1 facility will provide the
required LBO setting (transmit signal level) required for
connection to the T1 facilities. This value should be used
when setting the 1558D LBO transmit values (0, 7.5, 15,
or 22 dB) in the 1558D unit. If the value cannot be
obtained from the provider, the LBO transmit values for
Path A and Path B should be set to 0 dB.
4. Verify that the T1 line is operating properly before you
attempt to install the 1558D unit. Both of the T1 lines
should be checked for error free operation for at least one
hour to ensure that they are performing error free.
5. If the unit is to be in stalled in a 19’ equipment be rack,
verify that there is enough rack space available in the
rack (requires 1.75 inches per 1558D unit). Four pan
head (type 12-24 x 1/2 inch) screws are provided for
mounting the unit. An optional 23” rack mount kit is
available for applications using this size rack.
6. Verify that no external CSUs (channel service units) preexist at the location where the 1558D is being installed.
The 1558D unit provides internal ESF CSU functions and cannot operate properly if another
CSU is also co-located with the 1558D.
Unpacking and Inspection
This unit is carefully packaged to prevent damage in shipment. Upon receipt, inspect the shipping container for damage. If the shipping container or cushioning material is
damaged, notify the carrier immediately and make a notation on the delivery receipt that the container was damaged
(if possible, obtain the signature and name of the person
making delivery). Retain the packaging material until the
contents of the shipment have been checked for completeness and the instrument has been checked both mechanically
and electrically.
If the contents of the shipment are incomplete or, if there is
mechanical damage or defect, notify TxPORT. If the shipping container is also damaged, or the cushioning material
shows signs of stress, notify the carrier of the damage as
well as TxPORT. Keep the shipping materials for carrier’s
inspection. TxPORT will arrange for repair or replacement
without waiting for claim settlement.
Mounting
If the 1558D is to be installed in an equipment rack, simply
mount the 1558D in the equipment rack using the provided
mounting screws and rack mount adapters. If the equipment
is to be located on a desktop, remove the rack mount adapters and set the unit on any flat surface. Once the equipment
has been physically located, the following rear panel wiring
connections should be performed.
Wiring & Connections
There are several wiring connections that must be performed
to install the 1558D. The following paragraphs describe how
to attach the APS unit to the associated T1 lines, power connections, alarm connections, and COM BUS connections.
Figure 2 -1 should be used as a reference for the following
paragraphs concerning installation of the 1558D APS unit.
Chassis Ground Connection
The 1558D unit should be connected to a good earth ground.
To connect ground to the unit, attach a 26 gauge or larger
Installation 2-11558D APS CSU/DSU
wire from the rear panel screw terminal labeled ‘GND’ to a
good earth ground.
Voltages in excess of 100 VDC may be
present on the T1 telecommunications
lines. Before connecting the APS unit to telecommunication lines, ensure that the rear
panel screw terminal labeled ‘GND’ has been
connected to a good earth ground.
Alarm Connections
The 1558D has alarm contacts provided at the rear panel
screw terminals labeled ‘COMMON’, ‘NC’, and ‘NO’. The
alarm relay is operated when power is present to the 1558D.
To connect the APS alarm relay to an external customer
alarm surveillance system, perform the following:
• Connect a 26-gauge wire to the rear panel screw terminal
labeled ‘COMMON’ to the external alarm system.
• Connect a 26 -gauge wire to the rear panel screw terminal
labeled ‘ALARM NO’ (normally open) or to ‘ALARM NC
(normally closed) to the external alarm system. The alarm
relay is normally operated when power is connected to the
unit.
COM Bus Connections
The rear panel COM BUS connectors (IN/OUT) are used to
communicate to/from the optional APS 15 59 site manager.
These connections are only used when a 1559 Network
manager is co-located with the 1558D(s). Bus connections
from the manager to one or more 1558D units is done in a
daisy chain fashion. That is, the COM BUS Out from the
1559 is connected to the COM BUS IN of the 1558D and
the COM BUS OUT of the 1558D is connected to the COM
BUS IN of the 1559. Physically, the connections to the
COM Bus IN/OUT are RJ-11, 6-pin miniature modular
jacks. The function of the six pins associated with the jacks
are shown below in Table 2-D.
Table 2-D RJ-11 Pinouts
PIN CO M BUS INCOM BUS OUT
1Not UsedNot Used
2Signal GroundSignal Ground
3Data, outputData, Output
4Data, inputNot Used
5Signal GroundSignal Ground
6Not UsedNot Used
T1 Connections
All T1 lines are connected to the 1558D unit usin g modular
8-pin RJ-48 cables (two 10' RJ-48 cables come with the
unit). Insert the RJ48 connectors into the rear panel receptacles labeled NET A, and NET B. Connect the other ends of
the cable to the appropriate external T1 A and B facility
equipment. The modular RJ-48 Pinouts and their functions
are shown in Table 2-C.
Table 2-C RJ-48 Pinouts
Pin NET A & B, RJ-48
1 Data In, Tip
2 Data In, Ring
3 Not Used
4 Data Out, Tip
5 Data Out, Ring
6 Not Used
7 Not Used
8 Not Used
V.35 Interface
The 1558D high speed DTE port is a 34-pin female connection. The interface is fully compatible with CCITT V.35
standards. To connect external CPE equipment to the
1558D, simply attach a male V.35 cable to the V.35 DTE
port found at the rear of the 1558D. Be sure to mechanically
secure the cable in place by tightening the provided thumb
screws. The operating speed and clocking arrangements are
described in the section entitled Configuration Modes on
page 2 -3. The pinouts for the V.35 interface are shown in
Table 2-E.
Table 2-E V.35 Pinouts
FunctionCCITTName
Frame Ground101FGA
Signal Ground102SGB
Send Data103SDP, S
Receive Data104RDR, T
Request to Send105RTSC
Clear to Send106CTSD
Data Set Ready107DSRE
Direction
DTE/DCE
1558D
V.3 5
Installation 2-2
NET BNET A
COM BUS
ON
S1S2S3
IN OUT
OFF
V.35
ON
OFF
S4
ALARM
GND
N.O.
COM
N.C.
Figure 2-1 1558D Rear View
1558D APS CSU/DSU
Table 2-E V.35 Pinouts
FunctionCCITTName
Data Terminal Ready108DTRH
Data Carrier Detect109DCDF
Transmit Clock113,114TCY , AA
Receive Clock115RCV, X
External Clock113ext.TCU, W
Test Mode142TMK
Direction
DTE/DCE
1558D
AC Power
V.3 5
• Master or Slave Card Operation
• Boot general parameters from Switches, ROM, RAM, or
Manager
• Boot alarm parameters from ROM or RAM
• Enable/Disable Framing Error Alarm
• Enable/Disable Loss of Signal Alarm
• AMI/B8ZS Line Encoding, NET A, NET B
The following table describes the DIP switch settings co ntrolled by Switch S1.
The 1558D unit operate from 115 VAC, 75 mA maximum.
The unit is shipped with a 5.5 foot 3-prong industry standard
AC power cord. After all wiring connections have been
completed, attach the unit to the AC wall receptacle. The
unit responds by turning on the front panel (green) LED
power indicator. The user is now ready to configure the
1558D. The following sections describe how to quickly configure the 1558D unit.
Configuration Modes
Any time that the 1558D unit is initi alized (power removed,
then reapplied), all key configuration data is read by the
1558D CPU and implemented based upon the particular
configuration boot mode options selected by the user. There
are four possible configuration boot modes:
• Configure/Boot from Switches
• Configure/Boot from ROM.
• Configure/Boot from RAM.
• Configure/Boot from Manager. This requires the optional
1559 manager.
All factory default settings in this manual are
shown underlined.
Switch Configuration
After the equipment has been unpacked and inspected and
mounted, the next step is to configure the unit. All unit
options are set by the manual DIP s witch positions located
on the four rear panel option switches (S1, S2, S3, and S4).
The 1558D is shipped from the factory with all option
switches in the OFF (factory default) positions. The following paragraphs briefly describe the 1558D option switches
and there functions.
After the option switches have been set to the
desired operating mode, recycle the power to the
unit. At power up, the C PU will read and implement the switch settings.
O
PTIONSWITCH
Switch S1 is an eight position DIP switch used to set the
following unit options.
S1
.
Table 2-F Switch S1
Position SelectionSwitch S1 Description
1Off
2,3Off, Off
4Off
5Off
6Off
7Off
8Off
O
PTION SWITCH
On
Off, On
On, Off
On, On
On
On
On
On
On
Card Function, Slave
Card Function, Master
Boot from Switches
Boot from Manager
Boot from RAM
Boot from ROM
Switch S2 is an eight position DIP switch used to set the
following unit options.
• CSU Mode, Enable/Disable
• Path Revert, Enable/Disable
• NET A, LBO V alue
• NET B, LBO V alue
• Clocking Mode, Internal, External, Network
Table 2-G describes the DIP switch settings controlled by
Switch S2.
Table 2-G Switch S2
Position SelectionSwitch S2 Description
1Off
On
2Off
On
3,4
Off
, Off
Off, On
On, Off
On, On
CSU Mode, Enabled
CSU Mode, Disabled
Path Revert, Disabled
ON = Path Revert, E nabl ed
NET A LBO Value
0.0 dB
7.5 dB
15.0 dB
22.5 dB
Installation 2-31558D APS CSU/DSU
Table 2-G Switch S2
Position SelectionSwitch S2 Description
5,6
7,8Off
O
PTIONSWITCH
Off
, Off
Off, On
On, Off
On, On
, Off
Off, On
On, On
On, Off
S3
NET A LBO Value
0.0 dB
7.5 dB
15.0 dB
22.5 dB
Network Clock ing
Network Clock ing
Internal Clocking
External DTE Clocking
Switch S3 is an eight positio n DIP switch used to configure
the 1558D unit address ID for the NET A hardware and the
NET B hardware. Unique addresses must be optioned for
each 1558D unit when multiple units are co-located and a
1559 Site Manager is being used. If no manager is being
used, the user should leave the DIP switches in the factory
default positions (all in the OFF or DOWN position). This
configures the unit for NET A address 1 and NET B address
2. Table 2-H indicates how to configure the address settin gs
for the first six 1558D units.
Table 2-H Address Settings
*APS Mgr .
Unit Pos.
1.011/2
1.023/4OnOnOffOffOff
1.035/6OnOffOnOffOff
1.047/8OnOnOnOffOff
1.059/10OnOffOffOnOff
1.0611/12OnOnOffOnOff
NET A/B
Address
Pos1Pos2Pos3Pos4Pos
5 - 8
OffOffOffOff
Off
When connecting to the SUPV port using the
APS local access software, the 1558D NET A
and NET B addresses are viewed as a single unit
address and are displayed as 1.01 for addresses
1 and 2, 1.02 for addresses 3 and 4, etc.
O
PTION SWITCH
S4
Switch S4 is a ten position DIP sw itch used t o configure the
following DTE interface options.
• Set DSU Operating Speed (56kb - 1.536 Mbps)
• Set Rate Multiple, 56kb or 64kb
• Set DS0 Assignment Mode, Contiguous/Alternate
• Set Flow Control, On/OFF
• Set Data Invert, Yes/No
Switch 4, (Pos. 1 - 6) - These six DIP switches allow the
user to select the operating speed of the 1558D DTE port
and whether or not the DS0s are assigned sequentially,
beginning with DS0#1 or Alternately, beginning with
DS0#1, 3, 5, etc. The table below shows the option position
settings for the various combinations of speed and DS0
channel assignments. The 1558D can be configured to operate from 56 kb to 1.536 Mbps.
Table 2-I Speed Settings
Pos1Pos2Pos3Pos4Pos5 Pos 6
Off
(64Kb)
Off
OffOffOffOff15361 34424
OffOffOffOnOff1472128823
OnOffOffOnOff1408123222
OffOnOffOnOff1344117621
OnOnOffOnOff1280112020
OffOffOnOnOff1216106419
OnOffOnOnOff1152100818
OffOnOnOnOff108895217
OnOnOnOnOff102489616
OffOffOffOffOn96084015
OnOffOffOffOn89678414
OffOnOffOffOn83272813
OnOnOffOffOn76867212
OffOffOnOffOn70461611
OnOffOnOffOn6405 6010
OffOnOnOffOn5765049
OnOnOnOfOn5124488
OffOffOffOnOn4483927
OnOffOffOnOn3843366
OffOnOffOnOn3202805
OnOnOffOnOn2562244
OffOffOnOnOn1921683
OnOffOnOnOn1281122
OnOnOnOnOn64561
Pos 6
On
(56Kb)
DS0
Switch 4 (Pos. 7 - 10) - These option switches are used to
set the following:
• Contiguous or Alternate DS0 assignment
• Set control lines to either ON or OFF
• Enable or disable data invert feature
Table 2-J displays the various options/positions controlled
by SW4, positions 7 - 10.
Table 2-J Switch SW4-7 thru SW4-10
Position SelectionSwitch S4 Description
7OffOnContiguous DS0s
Alternate DS0s
8OffOnControl Lines (CTS, DSR,CD) are set
On
to
Control Lines follow (DSR follows T1
sync, CTS follows RTS, and CD follows T1 density status)
9OffOnData Invert Disabled
Data Invert Enabled
10—Not Used
Installation 2-4
1558D APS CSU/DSU
DS0 channel speed assignments are sequentially
assigned beginning with DS0 #1 if SW4, Position
7 is set to the OFF positi on (contiguous channel
assignment). When SW4, Position 7 is set to ON,
the channels will be assigned in alternate DS0s,
beginning with DS0#1, DS0#3, etc.
ROM Configuration
The 1558D may be configured to boot operational parameters from the internal ROM (read only memory). To configure the 1558D to boot from ROM, set SW1, Position 2 and
SW1, Position 3 to the ON pos ition and SW1, Positio n 6 to
the OFF position. With these settings, the 1558D will
always boot (at power up) the unit configuration parameters
from the internal ROM settings. The ROM unit parameters
set when the user selects ‘boot from ROM’ are listed below:
• Slave Unit Operation
• B8ZS line coding, Path A and Path B
• ESF framing, Path A and Path B
• Revert mode, Disabled
• A v ailability timer set to 60 seconds
• Errored seconds set to 20
• Consecutively errored seconds set to 2
• Loss of frame set to Enabled
• Loss of signal set to Enabled
When the 1558D is being configured to boot from ROM the
user must still review and set the manually selected operating parameters listed below.
• LBO transmit level setting for both NET A and NET B
• 1558D unit address (if optional 1559 manager is installed)
• DSU Operating Speed (56kb - 1.536 Mbps)
• Rate Multiple, 56kb or 64kb
• DS0 Assignment Mode, Contiguous/Alternate
• Flow Control, O n/O FF
• Data Invert, Ye s/ No
RAM Configuration
The 1558D can be optioned to boot all alarm and operating
parameters from the battery backed RAM at power up. To
configure the 1558D for this mode of operation, simply set
SW1 , P osition 7 to ON, and S W1, Pos ition 8 to OFF. Keep
in mind that the user must still manually configure the following unit operating features:
• LBO transmit level setting for both NET A and NET B
• 1558D unit address (if optional 1559 manager is installed)
• DSU Operating Speed (56kb - 1.536 Mbps)
• Rate Multiple, 56kb or 64kb
• DS0 Assignment Mode, Contiguous/Alternate
• Flow Control, O n/O FF
• Data Invert, Yes/No
Manager Configuration
The 1558D may be configured and controlled using the
optional 1559 APSM site manager. The manager, co-located
with one or more 1558D units (up to 56), provides both
local and remote access and control/ alarm reporting to one
or more remote locations. When the 1558D has been configured to ‘Boot from Manager’, the 1559 can access and
change all options except the following:
• LBO transmit level setting for both NET A and NET B
• 1558D unit address (if optional 1559 manager is installed)
• DSU Operating Speed (56kb - 1.536 Mbps)
• Rate Multiple, 56kb or 64kb
• DS0 Assignment Mode, Contiguous/Alternate
• Flow Control, O n/O FF
• Data Invert, Yes/No
• Boot Mode (Switches, RAM, ROM, Manager)
To configure the 1558D to ‘Boot from Manager’, set S1- 7
to OFF and S1-8 to ON. For additional information concerning the use and operation of the 1559 manager, refer to
the TxPORT 1559 APSM reference manual.
Unit configuration of the 1558D APS is now complete. The
final steps to complete installation is to perform the 1 558D
preservice testing steps describe in th e following sections.
Pre-service Testing
The pre-service test checks the operational integrity of the
1558D unit and the T1 facilities (Net A and Net B). The
local pre-service testing is made independen tly of any DTE
or T1 connections. The end-to-end testing requires that the
T1 facilities be connected to the 1558D unit.
Local 1558D Test Diagram, Path A and Path B on page 2 -
8 illustrates the testing described in the following pre-ser-
vice steps. Pre-service Testing verifies the following:
• Path Integrity for Path A and Path B (local)
• Path Integrity for Path A and Path B (end-to-end)
The following T1 test equipment and miscellaneous cables
will be required to perform the 1558D pre-service tests :
• A Data BERT Test Set with a V.35 Interface
• One V.35 cable (1558 to T est Set)
Before proceeding, the user should read and understand the
background information presented in the following paragraphs concerning the basic operation theory of an APS service (also refer to Figure 3- 1 on page 3- 2 and Figure 3 -4
on page 3-10).
Installation 2-51558D APS CSU/DSU
APS service is different from “normal” point- to- point T1
service. The 1558D APS unit accepts a single source signal
from the attached DTE equipment, verifies signal density,
duplicates the signal, and then transmits it on two T1 lines
(Path A, Transmit and Path B, Transmit). This duplication
and dual transmission is also done at the far-end APS equipment.
In addition to the un iqu e transm itting functi on p erform ed by
the APS, the unit also performs a unique receiving function.
There are two identical signals being received from two T1
lines by the APS equipment (Path A, Receive and Path B,
Receive). The 1558D constantly monitors both of these lines
for satisfactory signal performance. In the event that the
present active receive line exceeds an alarm value, the APS
will automatically switch the service from the failed receive
path to the standby receive path. The active receive signal is
the path connected to the DTE equipment.
Once a path has declared an alarm condition from Errored
Seconds, Consecutively Severely Errored Seconds, Loss of
Frame, or Loss Of Signal, it will not be available for service
until the Line Availability Timer has determined that the line
is available for service (line has run error free for the user
defined time period, 0 to 900 seconds, user definable). At
that time, the path alarm circuitry will be reset and then the
path will be ready to accept service.
Path A Pre-service Testing
Perform the following test steps to verify that the 1558D can
run error free data from the DTE V.35 port to the NET A
port and back (local loop test). The test setup for performing
this test is depicted in Local 1558D Test Diagram, Path A
and Path B on page 2-8.
4. Manually operate the front panel Path Select Switch to
the (A) position. This forces and locks the unit to Path A.
The following unit status LEDs associated with Path A
testing should be illuminated on the unit:
• Power A or B LED ON (green)
• Status ‘Locked’ LED ON (yellow)
• Status Path Active ‘A’ ON (green)
• The Path Status, Alarm A (red) LED may be ON or OFF
depending on the alarm timer setting (0 to 900 seconds)
configured in the 1558D.
5. The 1558D unit is now looped back to the V.35 DTE port
and the BERT test set should be running in sync and
error free. If not, verify that the test set speed and clocking settings are set to work with t he speed and clocking
options configured for the 1558D.
Path B Pre-service Testing
Perform the following test steps to verify that the 1558D can
run error free data from the DTE port to the NET B Port and
back (local loop test). The test setup for performing this test
is depicted in Figure 2-2.
1. Connect a data BERT test set to the DTE V.35 port at the
rear of the 1558D unit. The test set should be configured
to generate a BERT pattern (511, 2047, etc.) at the data
rate set previously by the user (56kb - 1.536Mbps). Also,
the test set clocking should be configured to operate per
the clocking options set in the 1558D (Internal, External). Typically, the 1558D will supply clocking to the
DTE equipment.
1. Connect a data BERT test set to the DTE V.35 port at the
rear of the 1558D unit. The test set should be configured
to generate a BERT pattern (511, 2047, etc.) at the data
rate set previously by the user (56kb - 1.536Mbps). Also,
the test set clocking should be configured to operate per
the clocking options set in the 1558D (Internal, External). Typically, the 1558D will supply clocking to the
DTE equipment.
2. Manually operate the DTE Loop Switch from the AUTO
position to the LL (L ocal Loop) positio n. This manually
loops the data coming from the DTE port back to the
DTE port.
3. Optionally, the user can insert a bantam test cord into the
NET A Bridge jacks (transmit and receive). This places a
metallic loop of the transmit signal of the 1558 D back to
the receive of the 1558D.
Verify that there is no connection at the NET A
jack when looping the 1558D at the Tx and Rx
bridge bantam jacks.
Installation 2-6
2. Manually operate the DTE Loop Switch from the AUTO
position to the LL (Local Loop) position. This manually
loops the data coming from the DTE port back to the
DTE port.
3. Optionall y, the user can insert a bantam test cord into the
NET B bantam Bridge jacks (transmit and receive). This
places a metallic loop of the transmit signal of the 1558D
back to the receive of the 1558D.
Verify that there is no connection at the NET B
jack when looping the 1558D at the Tx and Rx
bridge bantam jacks.
4. Manually operate the front panel Path Select Switch to
the (B) position. This forces and locks the unit to Path B.
The following unit status LEDs associated with Path B
testing should be illuminated on the unit:
• Power A or B LED ON (green)
• Status ‘Locked’ LED ON (yellow)
• Status Path Active ‘B’ ON (green)
1558D APS CSU/DSU
• The Path Status, Alarm B (red) LED may be ON or OFF
depending on the alarm timer setting (0 to 900 seconds)
configured in the 1558D.
5. The 1558D unit is now looped back to the V.35 DTE port
and the BERT test set should be running in sync and
error free. If not, verify that the test set speed and clocking settings are set to work with t he speed and clocking
options configured for the 1558D.
Standalone pre-service testing verifies the operational
integrity of the 1558D using both the A and B p ath circuitry.
If either Path A or Path B fails, but not both, and the options
have been verified, contact the TxPORT Customer Service
for additional assistance.
End-to-End Pre-Service Testing
The following paragraphs describe pre-service APS testing
of the 1558D when it is initially connected to the T1 facilities (Path A and Path B) and is configured with another
1558D APS at the far-end.
After completing the stand-alone pre-service test procedures, the 1558D is ready to be connected to the Path A and
Path B T1 facilities for verification of end-to -end operation. These test procedures will verify the following:
• End-t o-End Performance of Path A
• End-t o-End Performance of Path B
• Ability to generate remote V.54 loop of 1558D port
The following steps assume that there is a near end unit and
a far-end unit and a technician with a BERT test is at both
locations (near and far).
1. Attach the Path A and Path B T1 facilities to the respective NET A and NET B modular jacks at the rear of the
unit (both near and far locations).
should be error free
repeat test for another 15 minutes. If errors are still
detected, a problem exists in the T1 facility. Refer problem to appropriate channels for resolution.
After completing the end-to-end BERT testing of both Path
A and Path B facilities, verify that the remote V.54 loop
operates properly by performing the following steps.
1. To verify that the loop operates, simply move the DTE
manual loop switch from the AUTO to the RL (remote
loop position). The unit responds by:
2. TEST LED indicator turns On (amber) and the 1558D
internally generates a V.54 loop code to the far-end for ≥
five seconds.
3. After approximately five seconds, the TEST LED indicator will change from amber to green if the V.54 loop
operated at the far-end. If the loop did not operate, the
TEST LED will turn from amber to red which indicat es
that the far-end unit did not respond to the reques ted V.54
DTE loop.
The remote V.54 lo op will rema in active until the DTE manual loop switch is moved from the RL position back to the
AUTO position. When this is done, the 1558D will generate
an UNLOOP command to the far unit. After approximately
≤ five seconds the front panel TEST LED indicator will
change from green to off.
This completes the end-to-end operational check for the
1558D. Remove all test equipment and verify that both units
are attached to the T1 facilities (NET A and B) and verify
that the DTE high speed data application is attached. After
performing these checks, the 1558D unit is now ready to
fully support proactive automatic protection switching and
performance monitoring.
at both ends. If errors are detected,
2. At both locations attach the data BERT test sets to the
1558D DTE port making sure that the speed and clocking settings match those configured in the 1558D unit.
3. Operate the Service Select switch on the 1558D to the
Path A position at both the near and far 1558D units.
This forces both units to use Path A as the receive signal
source. Once this is done, both t est sets should indicate
pattern sync at both the near and far locations. Run test
for a minimum of 15 minutes. The test results should be
error free
for another 15 minutes. If errors are still detected, a problem exists in the T1 facility. Refer problem to appropriate
channels for resolution.
4. Operate the Service Select switch on the 1558D unit to
the Path B position at both the near and far 1558D units.
This forces both units to use Path B as the receive signal
source. Run tes t for a minimum of 15 mi nutes. The test
at both ends. If errors are detected, repeat test
Installation 2-71558D APS CSU/DSU
SUPV
SUPV
PWR
PWR
STATUS
STATUS
ALOCKEDB
ALOCKEDB
A
SELECT
A
PATH
SELECT
AUTO
PATH
AUTO
PATH
STATUS
ALM LOSLP
B
A
B
PATH
STATUS
ALM LOSLP
B
A
B
N
E
T
A
N
E
T
A
RX BRDG
TX BRDG
RX BRDG
TX BRDG
N
E
T
B
N
E
T
B
Bantam Patch Cord
Path NET A
RX BRDG
SDRD TEST
TX BRDG
RX BRDG
SDRD TEST
TX BRDG
PATH
STATUS
LOOP
NORM
RL
Bantam Patch Cord
Path NET B
PATH
STATUS
LOOP
NORM
RL
LL
LL
BERT Test Set
NET BNET A
COM BUS
IN OUT
1558A (near)
ON
S1S2S3
OFF
V.54 Loop Testing
Active Path (A or B)
V.35
DCE/V.35
DTE/V.35
Data Communications
BERT Test Set
Speed - 1.536 Mbps
Clocking - DCE
Pattern - QRSS
ON
OFF
1558A (Far)
ALARM
GND
N.O.
COM
S4
N.C.
DTE Port
Installation 2-8
V.54 Loop
Figure 2-2 Local 1558D Test Diagram, Path A and Path B
1558D APS CSU/DSU
3. Operation
The 1558D automatically switches a customer high speed
data application from a “defective” T1 service to a standby
facility. This capability minimizes any actual service ou tage
to the customer. Typically, switching from the active to the
standby path is transparent to the customer with minimal
impact on data services. The 1558D Automatic Protection
Switch (APS) equipment is compatible with AT&T TR
54017, Addendum, February, 1991. When the 1558D is configured for internal ESF CSU operation, it is fully compatible with AT&T TR 54016 ESF CSU requirements.
Applications
APS T1 protection service (per TR 54017) is either provided
by a Common Carrier (AT&T or MCI, etc.) or by the customer. When a Common Carrier provides the service, APS
equipment is installed in the central office and at the customer premise location(s). In the case of customer provided
APS, the customer installs a 1558D at both ends of the mission-critical service. Figure 3 -1 on page 3 - 2 depicts some
of the more common APS applications.
TxPORT APS equipment must be installed in pairs (one
TxPORT unit at one end of the service and another unit at
the other end of the service). One unit of the pair must be
configured for Master mode and the other as Slave mode.
Revertive and Non-Revertive Switching
The default configuration of the 1558D APS provides nonrevertive protection. Specifically, this means that service,
when transferred to the standby path, remains on the new
path until its performance degrades past the threshold settings. This is in contrast to the optional revertive mode
which returns service to the default path when it has
returned to a minimal level of error free performance.
Default Power-Up Path
The desire for geographically diverse routing may also
result in diversity in the medium of transmission (copper,
fiber, microwave, etc.). Certain media have higher intrinsic
performance criteria and are therefore the service of preference. To accommodate this preference, on power up, the
1558D APS unit forces the Path A as the active path.
Loss of Signal / Loss of Frame
When a LOS (Loss Of Signal) is detected on the active path
from the facility side of the APS, the 1558D will immediately switch the service to the standby facility (assuming
that the standby path is not in an alarm or a maintenance
state and the LOS alarm is enabled). If the standby path is in
an alarm state, the service will remain on the failed path
until the alarm condition clears on the standby path.
General Operation
The 1558D constantly moni tors the status and q uality of the
path signal (A and B) received on both the active access
path and standby access path. In general, the status and quality of the signal is based on the ESF parameters described in
Section 3.1 of TR 54016 and additional parameters
described in this document and in TR 54017, 1991. If the
performance of the active path is determined to be impaired,
the protection switching equip ment will au tomatically s elect
the standby access path if that path is ready for service (not
in an alarm or a maintenance state). The level of impairment
at which a transfer is accomplished is dependent upon the
alarm threshold values set in the equipment.
Following a switch, the former standby access path becomes
the active path. The 1558D continues to monitor both of the
incoming data streams after a switch has occurred. If both
active and standby access paths exceed their specified
thresholds, service will be maintained on the currently
active access path.
The switch from the active to the standby path is completely
independent of any external equipment. Switching from an
active path to a standby path only involves the receive paths
(Path A and Path B), not the transmit paths.
Optionally, in the event that there is a signal present but it is
so impaired that it results in a LOF (Loss Of Frame), the
1558D shall immediately switch after detecting 32 consecutive framing errors (approximately 93 milliseconds) to the
standby path (assuming that it is not in an alarm or a maintenance state and the LOF alarm is enabled).
Bipolar Violations
The 1558D APS units will not allow BPV
(Bipolar Violations) in the DS-1 data stream unless they are
used for B8ZS (Bipolar 8 Zero Substitution) encoding for
clear channel capability. Where used, the B8ZS code will be
employed to prevent the generation of an all zero octet.
CSU Loopbacks
Two ESF CSU loopbacks are provided in the 1558D unit
(CSU Line Loop and CSU Payload Loop). These loops can
be activated and deactivated by TR 54016 ESF messages, or
Inband per TR 62411. To insure maximum service availability, the following special conditions shall be applied to CSU
loopback actuation via the ESF data link messages:
• A CSU Line Loop or Payload can’t be activated on the
active path.
Operation 3-11558D APS CSU/DSU
• If the CSU Line Loop or Payload Loop activate signal is
received by both paths simultaneously, no change of LB state
shall occur, regardless of their current states.
The “one-way” protection characteristic of the APS can
result in split-service operation. That is, service from the
1558D near APS to the 1558D far APS via one access path
while the 1558D far APS to the 1558D near APS service is
on the other access path. This is desirable to minimize service disruptions. However, normal maintenance and fault
isolation techniques can’t be carried out while service is
being delivered in the split mode. Service to and from the
APS must be forced to a common access, either manually or
via maintenance message, before the standby path LB can
be activated.
Forced/Locked Capability
A manual path select control is provided on the APS which
selectively forces service to either Path A or Path B and
effectively inhibits the other path from accepting service.
The manual service select control supersedes all automatic
transfers and forces the path not inhibited to carry the service, regardless of its status or condition.
APS Switching Time
Two times are of significance in specification of the APS
protection switching function. Th e first is the latency period
between the point when the switching criteria is satisfied on
the active access path and the point at which restoration
occurs on the standby access path. This time is less than 50
milliseconds.
The second is the duration of the switching transient event
associated with physically moving service from the active to
the standby access path. The 1558D APS can complete the
transition from active to standby path within 1 bit time.
The decision to transfer service from the active path to the
standby path, and vice-versa, is based on a priority system,
where the highest priority condition that sat isfies a transfer
controls, regardless of the conditions in lower priorities.
• Priority 1 – LB Status:
If the standby path’s LB is activated, then service shall
remain on the active path.
• Priority 2 – Failed Status:
If the standby path is in a failed state then service shall
remain on the active path. A failed state could be a result of
excess ES, CSES, LOS, or LOF.
• Priority 3 – Error Event Threshold Criteria:
This level of transfer is based on the occurrence of 1 second
events within the current 15 minute interval as described in
the TR 54017 Addendum.
Each error event requires storage for the following values:
threshold setting, current count, and a service transfer flag.
The threshold setting for the events (ES and CSES) may
range from 1 to 900 seconds. Transfer of service is based
only on these events.
If the threshold of an event is 0, that event is inactive and is
not a criterion for transfer of service. The current count tallies the total number of error event seconds within the current 15 minute interval. This count is reset at the beginning
of a new 15 minute interval.
The service transfer flag is set for the event that causes a
transfer of service. It allows the cause of the service transfer
to be determined even after the current count has been reset
at the beginning of a new interval. This flag is reset when a
service transfer acknowledgment message is received, which
is described in the next section.
DTE
SlaveSlave
1
5
5
8
Master
Operation 3-2
T1, A
1
5
5
8
T1, B
1
5
5
7
Master
IXC Network
CO #1CO #2
1
5
5
7
Master
T1, A
T1, B
1
5
5
DTE
8
IXC Local Loop APS application, both ends
T1, A
T1, A
1
Telco and/or IXC Network
5
5
DTEDTE
8
T1, B
Customer Provided end-to-end APS Application
T1, B
Slave
Figure 3-1 Typical APS Applications
1558D APS CSU/DSU
APS Switching Parameters
Line Availability Timer
The 1558D unit switches from the active line to the standby
line based upon user definable alarm parameters. The alarm
performance parameters that can configured by the user are
Errored Seconds, Consecutively Severely Seconds, Loss of
Signal, and Loss of Framing. These alarm parameters and
their definition are described below.
Errored Sec onds (ES) - The user can define that the 1558D
switches from the active line to the s tandby line wh en a cer tain number of errored seconds have been detected during
the current 15 minute performance interval (900 seconds).
The ES threshold can be set from 0 (setting this p a rameter to
a zero value disables ES switching) to 900 seconds. The
1558D is configured at the factory with 20 errored seconds
as the default errored second value. The definition of an ES
is a second containing one or more CRC errors.
Consecutive Severely Errored Seconds (CSES) - Customers can define the 1558D switches from the active line to the
standby line when a certain number of Consecutive Severely
Errored Seconds have been detected during the current 15
minute performance interval (900 seconds). The CSES
threshold can be set from 0 (setting this pa rameter to a zero
value disables CSES switching) to 900 seconds. The 1558D
is configured at the factory with 2 consecutive severely
errored seconds as the default CSES value. The definition of
a CSES is when two or more consecutive SES have been
detected (note that CSES are transparent to the boundary
between 15 minute intervals). A severely errored second is
defined as a second containing 320 or more ESF errors.
Loss of Signal (LOS) - The user can define that the 1558D
switches from the active line to the s tandby line wh en a loss
of signal state has been detected. The 1558D is shipped
from the factory with loss of signal parameter enabled. The
definition of a loss of signal is when the receive signal from
the network contains ≥175 consecutive bit intervals containing all zeros (no pulses). The condition will be cleared when
one or more intervals contain a one.
Loss of Frame (LOF) - The user can define that the 1558D
switches from the active line to the s tandby line wh en a loss
of frame error state has been detected. The 1558D is shipped
from the factory with the loss of frame parameter enabled.
An LOF alarm condition occurs when 32 or more consecutive ESF frames contain frame bit errors.
When the current count of either ES or CSES is greater than
or equal to the threshold setting or when a LOS or LOF (if
enabled) is detected, the service shall be transferred from
the active path to the standby path as long as the standby
path is available (not in an alarm state or in a looped state).
A requirement for th e stan dby p ath to be available is tha t the
timer circuitry, described below, is not active and a LOS or
LOF condition does not exist.
The line availability timer is used to quantify when a path is
eligible to accept service.Line availability is determined by
the APS by observing a defined win dow of time in which no
active error events have occurred. The APS line availability
timer can be set to any value from 0-900 seconds. This
value represents the minimum amount of time, free of active
error events, that must expire before this path is declared as
ready to accept service. The factory default setting for the
line availability timer is 60 seconds.
The line availability timer requires storage for the timer setting and the active timer count. If the timer setting is 0, the
timer circuitry is disabled and the path is always available
for service, assuming that there are no active alarm conditions present. If the timer setting is set to a value ranging
from 1 to 900 seconds and a service transfer takes place, the
standby unit initializes the active timer count to the timer
setting. When the timer expires, thi s standby path becomes
available for a service transfer. This timed period must be
free of errors for all active events. If an error occurs, the
active timer count is reset.
When operated in the optional revertive mode, the path
availability timer serves to force restoration of service back
to the default access, Path A. That is, when service is
switched from Path A, it will remain on the standby path
(Path B) only until Path A’s availability timer expires. The
factory default is Revert set to OFF.
Status and Performance Information
The current status and performance parameters are stored in
the internal registers of the 1558D. Access to this information is via the 1559 APSM site manager (optional) or the
LAPS (local access protection switch) PC software. The
LAPS software is shipped with each 1558D unit.
The following information can be viewed by the user using
either the 1559 APS Site Manager or the provided APS
Local Access DOS Software.
• This path is currently carrying the service.
• This path is currently in a failed state.
• This path is currently in an inhibit state.
• The LB of this path is currently activated.
• The other path is currently in a failed state.
• The other path is currently in an inhibit state.
• The LB of the other path is activated.
• The manual locked control state.
• Current status
• Current interval Occurrences
• Current interval Duration
• Current Interval Timer
Operation 3-31558D APS CSU/DSU
• Occurrences - Intervals, 1 through 96
• Duration - Intervals, 1 through 96
• Valid Intervals Total
• Occurrences, 24-hour value
• Duration, 24-hour total
• 30-day switch occurrence history
Configuration Modes
Any time that the 1558D unit is initi alized (power removed,
then reapplied), all key configuration data is read by the
1558D CPU and implemented based upon the particular
boot mode options selected by the user (see Installation on
page 2-1 for additional information). The four possible
BOOT mode configurations are described below:
1. Boot from Switches - At power up, the 1558D CPU
reads the values set at the rear panel option switches and
configures the unit per those switch settings.
2. Boot from Manager - At power up the CPU sends a
message to the 1559 APS manager for a download of
1558D unit configuration information. Note that this
mode requires that a 1559 site manager be installed.
3. Boot from RAM - At power up, the 1558D CPU reads
the unit configuration from the battery backed RAM
data.
4. Boot from ROM - At power up, the 1558D CPU reads
the factory firmware default values from ROM. The factory default ROM configuration option settings are:
• Slave operation
• Net A/B B8ZS line coding
• Net A/B ESF framing
• Revert mode, disabled
• Av ai lability ti mer set to 60 seconds
• Errored seconds set to 20
• Consecutively errored seconds set to 2
• Loss of frame set to enabled
• Loss of signal set to enabled
Front Panel Functions
The front panel of the APS unit contains several LED indicators, a SUPV access port, a path select switch, and several
bantam test access jacks. The following paragraphs briefly
describe the operation of these items (refer to Figure 3- 2
and the 1558D Configuration at the end of this manual).
Access protection software) application. This user interface
software allows the user to gain access to the unit configuration data, unit status, unit performance, and perform local
and remote loopback testing.
Electrically, the SUPV port is RS232 and the data format is
19.2 Kb, asynchronous. The cable used to connect the PC to
the SUPV port is a DB9 (female) to 6-pin modular cable.
This cable is provided with the 1558D unit. The pin functions for the SUPV port are shown in the following table.
Table 3-A SUPV Pinouts
Pin SUPV Port Wiring
1Not Used
2Ground
3Data Out
4Data In
5Ground
6Not Used
Power Indicators
The 1558D has a green power LED indicator located on the
front panel. This indicator will be ON when the unit is connected to a nominal power source of 115 volts, AC. The
1558D draws approximately 75 milliamps. The AC power
cord is approximately 6 feet long and the plug end is an
industry standard 3-prong male connector.
Locked Indicator
The user can manually force and lock either the A or B T1
path as the active path by moving the PATH SELECT switch
from the AUTO position to either the A or B Path Select
positions. This action will force the 1558D to use the
selected path. Also, the 1558D is now manually locked to
this path and will not switch from it, even if the selected
path is in a failed state or subsequently fails. When the
1558D has been manually forced to either the A or B PATH,
the amber LOCKED LED indicator will be on. Moving the
PATH SELECT switch back to the AUTO position will turn
off the LOCKED LED and restore normal APS operation.
Placing the 1558D in a manually
locked mode prevents the unit from
performing automatic protection switching.
Status Indicators
The 1558D front panel STATUS A and B LEDs (green)
indicate which of the two T1 receive paths (A or B) is presently being utilized to provide service to the CPE equipment.
Supervisor Port
The front panel SUPV port allows the user to connect to the
1558D via a PC running the supplied APS LAPS (Local
Operation 3-4
Manual Path Selector Switch
The front panel manual PATH SELECT switch is used to
force the 1558D to use either the A or B path as the active
1558D APS CSU/DSU
line. If the user momentarily moves the switch to either th e
A or B position and then returns the switch to the Auto position, the 1558D will force s ervice to the s elected path (A or
B). If the user leaves the switch in the manual A or B p osition, the 1558D will LOCK the service t o this path and turn
on the LOCKED LED.
Placing the 1558D in a manually
locked mode prevents the unit from
performing automatic protection switching.
Path Status Alarm Indicators
The 1558D alarm circuitry is driven by the alarm parameters
defined by the user at time of installation. The user definable alarm parameters are ES (errored seconds), CSES (consecutive severely errored seconds), LOS (loss of signal),
LOF (consecutive ESF errored frames). When any of these
alarm thresholds are met or exceeded, the ALARM LED
indicator (red) will be on for the path (A or B) that has
“failed”.
Path Status LOS Indicators
The 1558D LOS (loss of signal) Path A and B indicators
(red) will be ON when no T1 pulses are being detected on
the receive signal paths from the network. The definition of
loss of signal is no pulses for 175 bit times. The loss of signal state will be cleared when one or more data pulses are
detected on the receive path. After the pulses are detected,
the respective LOS indicator will be turned OFF.
Path Status Loop Indicators
The 1558D can respond to CSU loop/unloop commands
(both inband and FDL) and local or remote APS loop/
unloop commands. When a loop has been activated (Path A,
B, or DTE) the respective front panel LP LED indicator
(amber) will be ON. If no loop is active, the LP indicator
will be OFF.
Bantam Test Access Jacks
Bantam test access jacks and bridge/monitor jacks are provided to gain physical access to the T1 Path A (NET A), and
T1 Path B (NET B) facilities. The placement of the jacks is
depicted in Figure 4-10 on page 4 -10. The function of these
jacks is described in the following table.
Table 3-B. Bantam Jack Functions
Path A/B J a cksFunction
Transmit (Tx) to
T1 facility (lower
left jack)
Receive (Rx) from
T1 facility (upper
left jack)
Transmit Bridge
(BRDG) to T1
facility (lower
right jack)
Receive Bridge
(BRDG) from T1
facility (upper
right jack)
Allows the user to gain access to the
transmit T1 path towa rd s the T1 f acil ity.
Inserting a test cord into this jacks disconnects the 1558D from the T1 facility
Allows the user to gain access to the
receiv e T1 path from the T1 fac ility.
Inserting a test cord into this jacks disconnects the 1558D from the T1 facility
Allows the user to bridge/monitor the
transmit T1 signal towards the T1 facility. Note, test set must be set to the
bridge termination mode.
Allows the user to bridge/monitor the
receiv e T1 sign al from the T1 fa c ility.
Test set must be set to the bridge termination mode.
DTE Status Indicators
Three DTE port status LED indicators provide a visual indication of the present state of the SD (send data), and RD
(receive data) signals. Also, the TEST LED indicates if a
manual or soft loop has been initiated by the user. A brief
description of these items is described in the paragraphs
below.
DTE SD LED
This LED (green) will indicate that data transitions are
present on the TD lead (from the DTE equipment). The
LED will be on for a mark and off for a space condition.
The LED will vary in intensity depending upon the relative
number of marks or spaces present at any given time.
DTE RD LED
This LED (green) will indicate that data transitions are
present on the RD lead (to the DTE equipment). The LED
will be on for a mark and off for a space condition. The
LED will vary in intensity de pending upon the relative number of marks or spaces present at any given time.
SUPV
PWR
STATUS
ALOCKEDB
PATH
SELECT
AUTO
A
PATH
STATUS
ALM LOSLP
B
A
B
RX BRDG
N
E
T
A
TX BRDG
N
E
T
B
Figure 3-2 1558D Front View
RX BRDG
TX BRDG
PATH
STATUS
SDRD TEST
RL
LOOP
NORM
TxPORT
1558D
APS CSU/DSU
LL
Operation 3-51558D APS CSU/DSU
TEST LED
This LED (tri-color amber, red, green) will indicate when
the DSU portion of the 1558D has been placed in a TEST
state either via remote loop command (V.54, Lp DTE Fac or
DTE Eq) or by placing the front panel manual loop switch
to either the RL or LL positions. The LED will be off when
the unit is not in a test state (no active loops either locally or
remotely). The LED will be ON (yellow when the manual
loop switch is in the LL position). The LED will be On
(yellow) when the manual loop switch is placed in the RL
(remote loop) position. In ð5 seconds, the yellow LED will
change to green if the far-end looped (V.54) or RED if th e
far-end did not loop.
Loopbacks
The 1558A unit supports several local and remote loopback
diagnostic capabilities allowing the user to quickly determine both facility and equipment problems. The types of
diagnostic loops that can be performed by the 1558 unit are:
• Manual Local Loop
• Manual Remote Loop
• Inband CSU Line Loop
• ESF Line Loop
• ESF Payload Loop
• V.54 Equipment Loop
The following sections will describe the operation and usage
of these loops. The reader should refer to Figure 3 on page
3-13 for additional information concerning the location of
these loops.
Local Manual Loop/Unloop
The 1558D unit provides a three position manual loop
switch located on the front panel. This switch allows the
user to initiate either a local 1558D loop or a remote loop of
a far-end 1558D unit.
To initiate a local 1558 loop, simply move the loop switch
from the NORM position to the LL (local loop) position.
The unit responds by; (1) loop ing back the transmit T1 signal (Tx towards the facility) back to the receive T1 signal
path (Rx from the facility) and, (2) turns on (yellow) the
front panel TEST LED indicator. Note that the manual local
loop forces a loop condition on both the A and B paths.
Once the loop is activated, any signals coming from the CPE
equipment are looped back to the CPE equipment. If a
BERT test set is attached to the 1558 DTE port, the user can
BERT test and verify the operation of either the A or B path
circuitry by moving the Path Select switch to either the A or
B positions.
To remove the local loop condition, move the manual switch
from the LL position back to the NORM position. The un it
will immediately remove the loops from both the A and B
paths and turn off the front panel TEST LED indicator.
Manual Remote Loop/Unloop
The near 1558D can initiate a manual remote 1558D lo op
of a far-end 1558D unit u sing an industry standard inband
V.54 loop code pattern. To initiate a far 1558D equipment
loop, manually operate th e front panel loop s witch from the
normal position to the RL (remote loop ) position. The unit
responds by performing the following:
1. Generates a V.54 loop pattern towards the far-end unit.
2. Turns on (yellow) the front panel TEST LED indicator
3. The far unit, after detecting the V.54 code for approximately 2 seconds, will initiate a V.54 equipment loop
(loops DTE port receive data back to send data plus
passes receive data to CPE equipment). See Figure 3.
4. After approximately 2 seconds, the near end unit stops
sending V.54 loop c ode and b egins running a ten seco nd
BERT test.
5. After running the BERT test for several seconds, the
front panel TEST LED indicator either turn GREEN if
the BERT test ran error free or turn RED if the BERT
pattern ran errors. Note that the errors could be caused
either by facility problems or by failure of the far-end
unit to loop.
To deactivate the remote loop, simply move the front panel
loop switch from the RL position back to the normal position. The 1558D responds by sending the V.54 unloop pattern to the far-end for approximately 2 seconds, afterwhich
the far-end unit will unloop and the both the near and far
unit TEST LED will turn OFF.
Anytime the 1558D has been manually placed in
a test state, the front panel TEST LED will be on.
Also note that the TEST LED will be on when
either a remote V.54 loop command has been initiated or when the unit has been command ed by
the 1559 to perform a CPE Equipment loop.
(V.54/CPE Equipment loop).l
Inband CSU Loop/Unloop
The 1558D will respond to industry standard inband CSU
loop/unloop codes. Operation of a CSU LLB (line loopback)
results from the 1558D receiving either a framed or
unframed repeating T1 pattern of (10000) for ≥5 seconds.
Upon receipt of this pattern for the prescribed time, the
standby path will loop the receive T1 signal (from the network) back to the transmit signal (to the network) and pass
the receive signal to the CPE (see Figure 3). Note that the
1558D will not allow a CSU loop of the active path. Also
note that when a loop is active on a given path, the associated front panel Loop LED indicator (yellow) will be on.
Operation 3-6
1558D APS CSU/DSU
The 1558D will unloop after receiving a framed or
unframed repeating T1 signal of (100) for ≥5 seconds.
When the unit unloops, the front panel Loop LED indicator
will go OFF.
ESF CSU Loop/Unloop
The 1558D will respond to industry standard ESF data link
loop/unloop messages. There are loop messages for a payload loop/unloop and a line loop/unloop. Note that the
1558D will only respond to a data li nk loop co mmand when
the path is in a standby mode (not actively carrying customer T1 service). Also note that the front panel Loo p indicator will be ON whenever the unit/path is in a looped state.
Local/Remote Soft Testing
Using the provided user LAPS software, the user can generate both local and remote 1558D loop/unloop commands
and BERT testing commands. The various types of loops
and BERT testing are discussed in detail in Chapter 4, LAPS
Operation.
Rear Panel Connections
All APS unit wiring connections and option switches are
located on the rear panel of the 1558D unit. The function
and description of these items are discussed in the following
paragraphs (refer to Figure 3 -3 on page 4 -7 and the 1558D
Configuration Guide).
Alarm Terminal Strip
A four position screw terminal is provided to connect the
1558D unit to ground and to an external alarm device. All
connections to these terminals strip should be made using
26 - gauge wire, or larger. The purpose of these terminals is
briefly desc ribed as follows:
Power
The 1558D operates from 115 volts AC. The maximum current draw is ð80 milliamps. A six foot indu stry standard 3pronged AC power cord is shipped with the unit.
Option Switches SW1 - SW4
The 1558D has four banks of DIP switches mounted on the
rear panel (SW1 - SW4). These option switches allow the
user to configure the 1558D to meet the various applications
that the user may require (see Installation on page 2- 1 for
additional information). The following paragraphs describe
these option switches.
O
PTION SWITCH
This 8 position DIP switch will be used to configure the
APS functions of the 1558D. The function of each of the
DIP positions is described below. Note that the factory
defaults are shown in bold type.
Posit i o n 1 - This DIP will be us ed to set the APS card function, Master/Slave
for status and can generate commands to the far unit. Slave
units can only respond to commands coming from a Master
unit. They cannot generate messages or obtain status from
far equipment. Note that 1558 units are installed in pairs and
only one of the units can be configured as a master. The factory default is SLAVE.
Positions 2, 3, - These positions will be used to set the
BOOT mode for the 1558D (Switches
factory default is boot from switches.
Posit ion 4 - This DIP will be used to set the ARM (Alarm
Relay Mode error parameters) function for the APS (ARM
from ROM
The ROM values are ES = 20, CSES = 2, LOS = Yes, and
LOF = Yes.
1
. A unit set to Master can poll the far-end
, ROM, RAM). The
/RAM). The factory default is ARM from ROM.
Ground: This terminal is used to connect the chassis
ground to an external earth ground.
Alarm Terminals (Com, NO, NC) : These three terminals
are used to connect the APS unit alarm relay contacts to
external alarm alert equipment. The APS unit alarm relay
contacts can be wired as Normally Open or Normally
Closed. The contacts are rated at 2 amps @ 30 VDC. When
the APS is powered, the alarm relay is in the operated state
and the NO (normally open) contacts are open and the NC
(normally closed) contacts are closed.
NET BNET A
COM BUS
ON
S1S2S3
IN OUT
OFF
Figure 3-3 1558D Rear View
Posit io n 5 - This DIP will be used to set the Framing Error
alarm, Enabled
/Disabled. The factory default setting is LOF
enabled. When enabled, the 1558D will declare an alarm
condition when 32 consecutive frame errors have occurred.
Posit io n 6 - This DIP will be used to set the Loss of Si gnal
alarm, Enabled
/Disabled. The factory default is LOS
enabled. When enabled, the 1558D will declare a LOS
alarm condition when a T1 receive signal contains 175 bit
times of no data transitions. The LOS condition will clear
when one or more data transitions have been detected.
V.35
ON
OFF
S4
ALARM
GND
N.O.
COM
N.C.
Operation 3-71558D APS CSU/DSU
Position 7 - This DIP will be used to set the AMI/B8ZS
function for NET A. The factory default setting is B8ZS.
The 1558D will automatically detect and insert a B8ZS code
into any block of data containing eight consecutive zeros.
Position 8 - This DIP will be used to set the AMI/B8ZS
function for NET B. The factory default setting is B8ZS.
The 1558D will automatically detect and insert a B8ZS code
into any block of data containing eight consecutive zeros.
O
PTIONS SWITCH
SW2
This eight position DIP switch is used to configure the following APS functions. The function of each of the DIP positions is described b elow. Note that the factory defaults are
shown in bold type.
Posit ion 1 - This DIP will be used to set the CSU En able
Disable mode. The factory default is CSU mode enable. If
the unit is set to CSU mode disable, the 1558D will not
respond to CSU ESF FDL commands nor will it res pond to
I-band CSU loop/unloop codes.
Position 2 - This DIP will be used to set the Path Revert
Enable/Disable
mode. The factory default is Path Revert disabled. If the unit is set for Path Revert enabled, the 1558D
will always revert the service back to the A path whenever it
is not in an alarm state.
Positions 3,4 - These two DIP switches configure the LBO
values for Path A (0.0
, 7.5, 15, or 22.5 dB). The factory
default is 0 db.
Positions 5,6 - These two DIP switches configure the LBO
values for Path B (0.0
, 7.5, 15, or 22.5 db). The factory
default is 0 db.
Positions 7,8 - These two DIPs will be used to set the
1558D timing source (Internal/Master, DTE/External, or T1/
Network) of the 1558D. The 1558D has an Auto Clockmode. This eliminates the need for the customer to loop
clocking back to the 1558D at the CPE end of the V.35 cable
in those applications where the customer is required to
return external clock leads to the 1558D unit.
O
PTION SWITCH
SW3
This eight position DIP switch is used to configure the unit
(shelf/position) address of the 1558D unit.
Positions 1,2,3,4,5,6,7,8 - These eight DIP positions are
used to set the unique unit address (see Ins tallation on page
2-1). The default address is 01
(all switches in the down
position).
O
PTION SWITCH
SW4
This 10 position DIP switch will be used to configure the
DSU functions of the 1558D.
Positions 1,2,3,4,5, - These DIPs are used to set the number
of DS0s used by th e DTE V.35 po rt (FT1). The operati on
will be the same as the p resent 300 productivity unit. Note
that DIPS 1 - 5 must be down and in this mode, the speed
will be set to 1.344Mb or 1.536 Mb, depending upon rate
multiple selected. The default is 1.536Mb
.
Posit ion 6 - This DIP will set the bit rate multiple to either
56 or 64 Kb. The default is 64Kb, clear channel
.
Posit ion 7 - This DIP will set the Contiguous or Alternate
DS0 channel mode. The 1558D can assign bandwidth either
in consecutive DS0 channels beginning with DS0 one or inb
alternate DSO channels beginning with DS0 one. The later
is sometimes required for fractional T1 service supplied by
AT&T. The default is Contiguous
.
Position 8 - This DIP will set the Control Flow mode to
either ON or Follows. The 1558D V.35 DTE port can be
optioned for control lines ON or follows. When set to ON,
/
the 1558D sets CTS, DSR, and CD to the ON state. When
set to FOLLOWS, the DSR follows T1 sync, the CTS follows RTS, and the CD follows the density status of the
incoming T1 signal (>175 zeros = CD OFF). Note that the
TM line goes high whenever the 1558D is placed in a test
state. The default is ON
.
Posit i o n 9 - This DIP will set the Data Invert mode to either
No or Yes. In certain data applications, the user data may
contain a high level of zeros and the user cannot operate the
T1 facility using B8ZS. In t his application, the 1558D can
invert the data, thereby maintaining T1 density requirements. The default is NO
.
Position 10 - This DIP is not used (spare)
V.35 Female Interface Connector (DCE)
The rear panel 34-pin V.35 female connector is used to
interface the 1558 to the CPE equipment. The pins used in
the interface and their functions are shown in Table 2-C.
Table 3-C. V.35 Female Interface Connector
FunctionCCITTName
Frame Ground101FGA
Signal Ground102SGB
Send Data103SDP, S
Receive Data104RDR, T
Request to Send105RTSC
Clear to Send106CTSD
Data Set Ready107DSRE
Data Terminal Ready108DTRH
Data Carrier De tect109DC DF
Transmit Clock113, 114TCY, AA
Receive Clock115RCV, X
External Clock113ext.TCU, W
Test Mode142TMK
Direction
DTE...1558
1558D
V.3 5
Operation 3-8
1558D APS CSU/DSU
DTE Control Lines
The DTE port can be optioned for control lines ON or follows. When set to ON, the 1558D sets CTS, DSR, and CD
to the ON state. When set to FOLLOWS, the DSR follows
T1 sync, the CTS follows RTS, and the CD follows the density status of the incoming T1 signal (>175 zeros = CD
OFF). Note that the TM line goes high whenever the 1558D
is placed in a test state.
COM Bus Connections
The two 6-pin modular connectors labeled COM BUS IN
and COM BUS OUT on the rear panel may be used to connect to the optional 1559 APSM site manager. These ports
are wired to allow daisy chaining one or more units off of
the APSM (the OUT port is connected to the IN port from
unit to unit). The COM BUS IN and OUT connectors are
physically RJ-11, 6- pin modular jacks. The function of the
6 pins are described in the table below. For additional information concerning the site manager, consult the TxPORT
1559 manual.
Table 3-D. COM Bus Pinouts
PIN COM BUS INCOM BUS OUT
1Not UsedNot Used
2Signal GroundSignal Ground
3Data, outputData, Output
4Data, inputNot Used
5Signal GroundSignal Ground
6Not UsedNot Used
Network T1 Connections
The NET A and the NET B T1 modular jacks are used to
connect the 1558D to the T1 facilities u sing RJ-48 modular
cables. Physically, the 1558D NET A and NET B connectors are RJ48, 8 - pin modular connector. The usage of each
of the eight pins found in the connector are described in the
table below. The 1558D unit comes with two ten-foot RJ-48
cables (NET A, NET B, and DTE).
Table 3-E. T1 Connections
PIN NET A NET B
1Data In (Tip)Data In (Tip)
2Data In (Ring)Data In (Ring)
3,6Not UsedNot Used
4Data Out (Tip)Data Out (Tip)
5Data Out (Ring)Data Out (Ring)
7,8Not UsedNot Used
Operation 3-91558D APS CSU/DSU
Tx Clk
Ext Clk
Rx Clk
TM
DSR
CD
RTS
V.35 Interface
APS
Select
Path A/B
A
B
Deframer
PLB
Framer
Fac/Local
Loop
Line
Loop
+5 VDC
±12 VDC
Power
Supply
Bridge
Jack
Bridge
Jack
Receive
Transmit
NET A
AC Input, 110 VAC
Jack
Jack
NET A
Line
Protection
Line
Protection
Rx
NET
A
RJ-48
Tx
RD
SD
COM Bus
IN
COM Bus
OUT
Alarm
Contacts
(COM,
NO, NC)
Eq/V.54
Loop
Loop
Set/Reset
CPU
ROM
RAM
SUPV
Performance History,
Alarms, Unit Address
Signal
Split
Port
Deframer
Fac/Local
PLB
Loop
Framer
Figure 3-4 1558D APS CSU/DSU Block Diagram
NET A
BERT: QRSS,
1:8, 3:24, etc.
NET B
Line
Loop
Bridge
Jack
Bridge
Jack
NET B
Receive
Transmit
NET B
Jack
Jack
Line
Protection
Line
Protection
Rx
NET
B
RJ-48
Tx
Operation 3-10
1558D APS CSU/DSU
4. LAPSOperation
Access to key 1558D configuration, performance, and testing functions can be locally performed by the user by
installing the provided 1558D LAPS (Local Access Software) on a PC and attaching the provided PC to 1558D
cable to the front panel SUPV port.
It is important that the user understand that the LAPS software provides only limited testing functionality and is solely
intended to provide a basic user interface to the equipment.
If more advanced access and testing is required, the user
should consider using the 1559 APS manager unit.
The following sections briefly describe the features and
functions of the 1558D LAPS software (Local Access Protection Switch) and how to install the software on a PC.
LAPS Installation
It is recommended that the user copy the LAPS software to
a directory on the PC hard drive and then store the original
disk in a safe place. The following steps will assist the user
in installing the LAPS software.
1. Power up the PC to be used and insert the LAPS software
into the A floppy drive. From the C drive DOS prompt
enter the following command:
C:\> md laps
The PC creates a directory on the C drive named LAPS
2. At the DOS command line, enter the following:
C:\> cd laps
The PC responds by displaying C:\LAPS
4. The PC copies all files to the directory called LAPS.
When the prompt indicates that all files have been copied, remove and store the original disk in a safe place.
5. After removing the disk in drive A, enter the following:
C:\LAPS> laps 1(or laps 2)
Entering ‘LAPS 1’ or ‘LAPS 2’ directs the program to
use either COM 1 or COM 2. T he computer responds by
launching the LAPS application. Once the application is
running, the user log on screen is displayed and the user is
prompted to “Press the Enter key to begin”. Once the
<enter> key is pressed, the LAPS main menu is displayed.
6. Attach the provided PC/LAPS data cable from the PC
COM port to the SUPV port on the 1558D.
The user should read the following LAPS user interface
information before attempting to use the LAPS software.
Screens And Menus
Common Screen Elements
The LAPS user interface is a menu driven system. The
available menus for the LAPS interface are shown in Figure
4-1. Each LAPS screen has several components that are
common to all screens and will be discussed in this secti on
only. The following paragraphs cover each of these components individually. Refer to the Main Menu screen (Figure
4 -3 on page 4 - 2) which depicts these common screen elements.
3. From this prompt enter the following DOS command:
C:\LAPS> copy A:* .*
Log OnLog Off
Circuits
in Alarm
Switch Occurrence History
Circuits
in Test
Performance
Circuit
Listing
Figure 4-1 LAPS Menu Tree
Date and Time: The top right corner of the LAPS screen
always displays the current date and time. The date and time
can be set as described in the Utilities Screen on page 4-9.
MAIN MENU
ConfigurationUtilitiesMaintenance
DateTimeHeaderAuto Log off
LAPS Operation 4-11558D APS CSU/DSU
Revisions: The LAPS software revision level is shown
below the time. Refer to these numbers when contacting the
factory with hardware or software related inquiries.
Location Header: The location name is displayed in the
center of the second display line.The header can be changed
under the Utilities menu.
Menu Title: Th e menu title (fourth line, center) d enotes the
general classification of the user interface that the user presently has accessed.
Messages: The message lines (bottom two) show alerts,
error messages, help messages and to accept typed, user
input. The use of typed input will be expanded upon in sections of this manual where it is directly applicable.
Alarms and Tests Messages: The right hand side of the
message line is used to alert the user that there are active
alarm or test states present in the unit. If their are active
alarms or circuit test states, the message line will display
“Alarms and/or Tests”. If there are no circuits in alarm or in
test, the Alarms/Tests message will not be displayed.
Cursor Controls
The LAPS software utilizes a highlighted cursor to make
selections from menus and to select fields within screens
that are to be operated upon. The cursor can be moved using
the standard terminal cursor control keys, which are <back-
For PC computers which do not have these particular keys
or have only some of them, a set of cursor control commands are supported. Each of these commands is effected
by holding down the <Ctrl> key while pressing a command
key. The available commands are listed in the following
table. These commands may be freely mixed with the use of
the normal cursor command keys at the user’s discretion.
Table 3-F Keyboard/Alternate Commands
Keyboard CommandAlternate Command
< left arrow >< Ctrl - S >
< right arrow >< Ctrl - D >
< up arrow >< Ctrl - E >
< down arrow >< Ctrl - X >
< backspace >< Ctrl - H >
< delete >< Ctrl - Z >
<page up><Ctrl - R>
<page down><Ctrl - C>
<update display><Ctrl - U>
Copyright 1991 TxPORT, All rights reserved
TxPORT APS Manager
Thu Jun 22 09:55:34 1995
Press Enter to begin
Figure 4-2 Log-on Screen
TxPORT 1559 APS Manager Date: MM/DD/YY
--------------------------------- Main Menus -----------------------------------
Circuits in Alarm
Circuits in Test
Circuit List
Maintenance
Configuration
Utilities
Log Off
Once the user has booted the LAPS software and connected
the PC to the SUPV port of the 1558D unit, the Log On
screen will appear on the PC display (see Figure 4- 2). To
access the LAPS user menus, press the <Enter> key. The
LAPS system responds by displaying the LAPS Main Menu.
(see Figure 4-3).
Main Menu Screen
The Main Menu lists the main functions that the user can
select and access. The primary user interfaces are shown in
the Menu Tree (Figure 4-1 on page 4-1) and the MainMenu screen (Figure 4-3 on page 4-2). Use the terminal
arrow keys or cursor control commands to highlight the
desired submenu. Once a selection has been made, press
<enter> to activate it. Refer to the cursor control commands
detailed in Cursor Controls on page 2-2.
The Main Menu and any subsequent sub menu may be
exited by pressing <esc>. If the Main Menu is exited, LAPS
returns the user back to the Log On screen. This is a valid
way to end a user session. If any other menu is exited, the
user is returned to the previous screen. The following sections discuss the key user submenus and their uses.
Circuit List Screens
Circuits in Alarm
The Circuits in Alarm screen displays a list of all circuits
which currently are in an alarm condition. Not that any
1558D units that have been placed in an Out of Service or
Unused state do not report alarms. Only 1558D units that
are in an In Service state and are in alarm will be posted to
the Circuits in Alarm display.
The Circuits in Test screen displays a list of all circuits
which currently are in test mode. A ci rcuit is deemed to be
in test mode if it has any kind of a loop establ ished. Circuit s
do not have to be “In Service’ to be in test mode.
Circuit List
The Circuit List screen (Figure 4 - 4) lists all circuits known
to the 1559 and their Near and Far operational statuses.
Circuit List Screen Manipulation
The three screens involving a circuit list (Circuits in Alarm,
Circuits in Test, and Circuit List) are all displayed and
manipulated in the same manner. Each circuit’s identification and status is displayed using the following fields.
Pressing the <esc> key will take the user back to
the previous circuit list screen.
Pos: This field specifies the circuit’s unit address. Stand
alone 1558D units are assigned address starting with shelf 1,
position 1, 2, 3, etc. The factory d efault address setting of a
1558D is shelf 1, position 1 (1.01). Additional info rmation
concerning the unit address is discussed in the Installation
sections of this manual beginning on page 2-1.
State: The current state of the circuit has the following possible definitions:
Unused:The circuit has never been installed or con-
figured.
Out Service: The circuit has been: 1) manually taken out
of active service, 2) installed but never put
into service, or 3) configured but never
installed.
In Service:The circuit has been installed and configured
and is currently in use.
Circuit ID: The first line in this field is the circuit name
assigned by the user for the NET A T1 facility. The second
TxPORT 1559 APS Manager Date: MM/DD/YY
-------------------------------- All Circuits ----------------------------------
Pos State Circuit ID Near Far
1.01 In Service HICAP 1234 Active Active
HICAP 5678 StandBy StandBy
line is the circuit name assigned by the user for the NET B
T1 facility. Circuit names are defined by the user with the
Configuration menu (Figure 4-8 on page 4-7).
Near: This field shows the current status of a protected
span’s two T1 lines as viewed from the 1558D unit that you
are attached to. This status is derived from error conditions,
communications failures, and user activated manual and soft
inhibits. The top line in the field depicts the status of T1
Line A. The second line depicts the status of T1 Line B.
This field will show one of the following status i ndicators
for each line:
(dashed line)No status is available for this circuit.
Active:The 1558D is actively using the received
signal from this line and the line has no
alarm conditions.
StandBy:The 1558D is not
actively using this line, but
it is not in an alarm condition and may be
used if needed by the 1558D APS unit.
Failed:This line has an alarm condition and is
therefore in a failed state. The APS may not
switch to this line.
Soft Inhibit:The user has initiated a soft inhibited com-
mand to the 1558D. When in this state, this
line may not be the APS equipment to provide user service.
Man. Inhibit: The user has inhibited this line from usage
by placing the front panel Select Switch to
either the A or B position. When in this
state, this line may not be used by the APS
equipment.
Reset:This line is in a reset conditio n. A momen-
tary status that may appear at the time the
attached APS is reset.
PL LP:This line has a payload loop active.
Line LP:This line has a line loop active.
Fac. LP:This line has a facility loop active.
Eq LP:This line has a equipment loop active.
CSU Loop:This line has a CSU loop active. This status
only appears for far end units.
Far: This field shows the current status of the protected
span’s T1 lines as received at the far end 1558D unit. The
content of this field is the same as that defined above for the
“Near” field. Note that only 1558D units configured as Master will display both Near and Far status. A 1558D configured as a Slave
will only display valid status for the Near,
not the Far.
The circuits are displayed in order by the shelf number and
the position within the shelf (unit address). Each Circuit List
Screen shows a maximum of six circuits at one time. The
next six circuits, if any, can be viewed by pressing <page
down>. To show the six preceding circuits, press <page up>.
An individual circuit can be specified at any time by entering the position designator at the message line prompt,
Shelf/Pos: and pressing <enter>. This designator must be
typed as it is displayed. For example, the APS device in
position 3 of shelf 1 would be specified as ‘1.03’ or ‘1.3’.
In any circuit list, a single circuit’s position designator will
always be selected by a highlighted cursor. The cursor control keys may be used to move this cursor from one circuit
to another. If the cursor is moved down from the last position on the screen, the circuit list will scroll up, showing the
next successive selection at the bottom of the screen. If the
cursor is moved up from the top of the screen, the list will
scroll down.
The cursor’s position is used to select a specific circuit for
displaying detailed performance data. Pressing <enter>
while a circuit is selected will cause a Performance S creen
to be displayed for that circuit. This screen is only accessi-
ble from the three types of circuit screens discussed in this
section.
Performance Screen
The Performance screen (Figure 4-5) is only accessible
from the Circuits in Alarm, Circuits in Test, and Circuit List
screens. The Performance screen allows the user to view
detailed performance data for a particular circuit.
In addition to the normal fields in the top section of the
screen, the Performance Screen shows the circuit’s two ID
headers along with the circuit’s position designator. All of
these are found in the upper left corner of the display.
Pressing the <esc> key will take the user back to
the previous circuit list screen.
The Performance screen contains four fields which can be
altered by the user. The function of these three fields is discussed in the following paragraphs:
Target: Signifies which section of the selected circuit is
presently displayed. Pressing <space bar> will change this
field to the next selection. The choices are: ‘Side A, Near’,
‘Side B, Near’, ‘Side A, Far’, and ‘Side B, Far’. Far Targets
can only be accessed if the far unit is a slave 1558D.
‘Near’ refers to the data received by the 1558D that the user
is physically attached. ‘Far’ refers to the data received at the
1558D unit at the remote or far end. Detailed information is
displayed for each selection as described in the following
paragraphs.
Reset ESF Events: This field is both a display field and a
user command field. It shows the running total of ESF error
events for the circuit section selected in the ‘Target’ field.
This count accumulates until it reaches 65535 or is reset by
the user. The count can be reset by moving the highlighted
cursor to this field and pressing <enter>.
Reset Event Regs: This is a command field. Moving the
cursor to this field and pressing <enter> will cause all interval data for the selected circuit section to be cleared.
SWO History: This command field is used to access the 30
day Switch Occurrence History screen. To access this information, move the cursor highlight to the SWO History field
and press <enter>. The system responds by displaying the
Occurrence History display (see Figure 4 -6). This display
lists the last thirty day completed periods (24 hours) and the
number of switch occurrences for each of those days. The
remainder of the fields in the Performance Screen are for
display only. They are defined as follows:
Status: The s tatus of the currently selected circuit section.
This status is the same as that detailed for “Near/Far” on the
previous page.
24 Hr.% Error Free: This is the percentage of intervals
that were error free in the last 24 hours or since the event
registers were last cleared.
Completed Intervals: The number of 15 -minute intervals
for which performance data has been collected. The maximum number is 96 (there are 96 fifteen minute intervals in a
24 hour period).
Event Free Intervals: The number of intervals that performance data has been collected without ESF error events.
(Interval Data): Per AT&T technical references 54016
and 54017, the interval data consists of Errored Seconds
(ES), Consecutive Severely Errored Seconds (CSES), Loss
of Frame Count (LOFC), Switch Occurrences (SWO), Duration (DUR), Unavailable Seconds (UAS), Severely Errored
Seconds (SES), and Bursty Errored Seconds (BES). The
value of each of these parameters is displayed for the current
interval for the total of the last 24 hours, and for each valid
interval in the last 24 hours.
The parameters shown on the Performance
Screen are updated in one minute intervals. An
update may be forced by pressing <Ctrl - U> on
the keyboard.
The CSES field is updated once every two seconds. This is done because CSES is a self-
clearing field and CSES events might not be
viewed if the CSES field was updated at a slower
rate.
The Position, State, Circuit ID, and Status of the currently
selected circuit will be displayed near the top of the Maintenance Screen. The format of this data is the same as that
detailed previously in the Circuit List (page 4-3).
The highlighted cursor marks the currently selected field
within the Maintenance Screen. Selections within any of the
fields may be changed by pressing <space bar>. A new field
may be selected with the terminal arrow keys or cursor control commands. A new selection is activated when <enter>
is pressed with the cursor still p ositioned on that field. The
actions initiated by each field are detailed below:
Maintenance Screen
The Maintenance Screen (Figure 4-7)allows the user to
perform test and maintenance functions on a selected circuit.
Upon entering this screen, the selected circuit will be the
last one chosen on any previous screen. The circuit can be
changed at any time by typing a new circuit shelf / position
number. It makes no difference which field is currently
highlighted as long as the ‘Shelf /Pos:’ prompt is showing
on the bottom display line. The selected circuit can also be
decremented or incremented by pressing <page down> or
<page up> respectively.
Maintenance testing can only be performed on
circuits whose status is not “ACTIVE”. It is recommended that the user place the circuit in an
“OUT of Service” state to prevent the generation
of alarms during testing. This is done by go ing to
the Circuit Configuration user interface and
changing the Service Status field from In Service
to Out of Service. After completing maintenance
testing, the unit Service Status should be
changed back to In Service.
Clear Tests: Resets any active loopbacks, locked paths (A
or B) and turns off any applied test pattern.
Clear Alarms: Resets alarms at the specified end of the
circuit (Near/Far). The choices are “Near / Far”.
Force: Causes the selected line (A or B) to become the
active line. If the selected line was previously locked, this
command will also serve to unlock it. The choices are: Side
A, Near / Side B, Near / Side A, Far / Side B, Far.
Lock: Causes service to be locked to the selected line. If
the selected line is currently in standBy, the APS will switch
to the selected line before locking. The choices are: Side A,
Near / Side B, Near / Side A, Far / Side B, Far.
Unlock: Unlocks the selected end of the protected span so
that the APS is allowed to use either line. The choices
are: Near / Far.
Target: Allows the user to select which T1 line that the test
is to be applied to. Note that you are not allowed to apply
any test conditions to the “ACTIVE”” T1 line. The choices
are: Side A / Side B.
Loop: Causes the selected loo p to be initiated on the line
selected by ‘Target’. The LAPS software does not check the
validity of the loop command. It is possible for the user to
specify a loop that is illegal (i.e. looping the active line). No
error message will be generated but the illegal action will
not be executed. The choices are: Near Payload, Near Line,
Near Facility, Near Equipment, Far Payload, Far Line, CSU,
and Net. If the unit has been configure for “CSU Mode Disabled”, the only loop available for the “Far” unit is NPC
Payload. Note that Far items are on ly valid if unit is configured for Master operation. Loop descriptions and operation
are discussed on page 4-9.
When ‘Net’ is chosen as the type in the Loop or
Unloop field, the user has the option of specifying the 5-bit pa ttern to be transmitt ed. Using the
arrow keys or cursor control commands, the user
may move the cursor to the bit field. A five- bit
pattern of 1s and 0s may then be typed by the
user.
Unloop: Takes down the specified loop. If the loop is controlled by ESF data link comm ands , th e respon se is im mediate, If the command is an inband command, the response
takes a minimum of 5 seconds.
Pattern: Specifies which pattern will be transmitted during
test. When the 3 or 5-bit, user-d efined pattern is chosen , the
user may type in any pattern of ones or zeros to be transmitted. Pressing <enter> with the cursor p ositi oned on th is field
will cause the pattern to be transmitted for the period of time
specified in ‘Test Time’. The choices are: QRSS, 1:8, 3:24,
all Ones, all Zeros, user definable 3- bit, and user definable
5 - bit.
Te s t T i m e : Defines the ru n- time o f test pattern generation
and error accumulation and starts the test. Pressing <enter>
with the cursor positioned on this field will cause the
selected pattern to be transmitted for the specified period of
time. If the Maintenance menu is exited, pattern testing is
halted. The choices are: 15 Minutes, 30 Minutes, 45 Minutes, 1 Hour, and Continuous.
Runtime: Shows the amount of time elapsed since a timed
Pattern test began. Note that this field only appears on th e
screen when a test is running.
Near CRC Errors: A display-only field for viewing the
number of CRC errors which are received at the Near Target
receive path.
Far CRC Errors: A display-only field for viewing the
number of CRC errors which are received at the Far Target
receive.Far CRC Errors are only reported if the 1558D is
configured as a Master. Slave 1558D units do not report Far
CRC Errors.
Reset Errors: Pressing <enter> with the cursor positioned
on this field causes both the Near and Far CRC accumulators to be cleared.
Configuration Screen
The Configuration Screen (Figure 4- 8) allows the user to
both view and set the configuration parameters for the
1558D equipment. A circuit may be configured at anytime,
before or after the hardware is installed. To implement
changes in the unit configuration, first place the Service
State to the Out of Service or Unused state. The LAPS software will not allow a user to change the configuration of an
IN SERVICE unit. Once one or more fields have been modified, the user must press <enter> or attempt to exit the
screen by pressing <esc>. The user will then see the promp t
“Accept changes?” ( Y/N )’. If the user responds by pressing
<Y>, only then will the configuration changes take effect. A
response of <N> will cause LAPS to ignore all requested
changes and to restore the original unit configuration param-
TxPORT 1559 APS Manager Date: MM/DD/YY
-------------------------------- Configuration --------------------------------Shelf/Position: [1.01] Circuit A: HICAP 1234
Net End: [NEAR] Circuit B: HICAP 5678
Service Status: [Out of Service]
Revision:1.00/1.00 Type: APS1558D
------------------------------------ Actual -----------------------------------Errored Seconds: [20] Speed Multiple:64Kb
Consecutive SES: [2] Clock:Network
Line Avail. Timer: [60] DSU Speed:768 Kb
LOS State: [ON] DS0s:Alternate
LOF State: [ON]Data Invert:OFF
Revert: [OFF] Control Lines: ON
Fac. Side A linecode: [B8ZS
Fac. Side B Linecode: [B8ZS]
A: LBO Level o dB
B: LBO Level o dBBoot from: Switches
eters. If the screen is exited with a <N> response, reentering
the Configuration Screen will show that all fields have been
returned to their previous values.
Configuration Screen fields have the following functions:
Shelf/Position: Defines the circuit that is being co nfigured.
This field may be changed by typing a new value or by
incrementing or decremented it with the <page down> and
<page up> keys, respectively. The unit is configured at the
factory for as address “Shelf 1.0”.
Net End: Defines which end of the circuit is being configured or viewed. The choices are: Near / Far (Far only available if 1558D is configured as a Master)
Service Status: Indicates the service status of the circuit.
This field also determines if the remainder of the fields in
this screen can be changed or only viewed. The following
selections may be made for this field:
In Service: The circuit is currently in service and all alarm
and Call on Alarm features are functional. No
configuration parameters can be altered for a
circuit that is in service.
Out Service: The circuit is not currently in service. Alarms
will function but the LAPS will not show the
circuit on the Circuits In Alarm display. Also,
if the optional 1559 site man ager is installed,
the 1559 will not initiate a Call on Alarm. All
other fields may be altered as described in the
following paragraph s.
Unused:No circuit has been defined for this Shelf/Posi-
tion.
Revision: This field displays the actual hardware and software revision for this unit and the unit type (1558A, 1558D,
etc.).
Circuit A: This field displays the descriptive name/ID of
Line A of the pair of T1 lines connected to the 1558D.
Circuit B: This field displays the descriptive name/ID of
Line B of the pair of T1 lines connected to the APS.
Actual/Database: This display only field indicates to the
user when the configuration data is being obtained from the
card (actual) and when the information is not being o btained
from the card but from stored information in either th e APS
manager or from the LAPS user interface (database).
Errored Seconds: This field is used to define the Errored
Seconds threshold for an APS service (as specified in
AT&T TR54017). The value may be set from 0 to 900. The
factory default value is 20 errored seconds.
Consecutive SES: This field is used to define the Consecutive Severely Errored Seconds threshold for an APS service
(as specified in AT&T TR54017). The value may be set
from to 0 to 900. The factory default value is 2 consecutive
errored seconds.
Line Avail. Timer: This field sets the time interval for
which each path’s Line Activity Timer remains active. The
value can be set from 60 to 900 seconds. The factory default
is 60 seconds.
LOS State: This field determines if the circuit’s APS will
alarm on Loss of Signal error state. If On is selected, the
1558D will alarm immediately on LOS. The choices are:
Off / On. The factory default is ON.
LOF State: This field determines if the circuit’s APS will
alarm on Loss of Frame error state. If On is selected, the
1558D will alarm immediately on LOF. The choices are:
Off / On. The factory default is ON.
Revert: If this field is set to On, the 1558D will always
restore the APS service back to the NET A path when the
NET A path meets the following criteria; (1) no alarm conditions are active on the NET A path, and (2) the Line Availability timer setting has expired (0 to 900 seconds, user
definable). The REVERT field can be set to either ON or
OFF. The factory default is OFF.
Fac. Side A Line code: Sets the facility side line coding
for Line A. The choices are: AMI / B8ZS. The factory
default is B8ZS.
Fac. Side B Line code: Sets the facility side line coding
for Line B. The choices are: AMI / B8ZS. The choices
are: AMI / B8ZS. The factory default is B8ZS.
LBO Level, A: Displays the option setting of the LBO
level select switch for network Line A. This field is a read
only field and may only be manually changed by the user
(see Installatio n on pag e 2-1). The fact ory defau lt setting i s
0 dB.
LBO Level, B: Displays the setting of the LBO level select
switch for network Line B. This field is a read only field and
may only be manually changed by the user (see Installation
on page 2-1). The factory default setting is 0 dB.
Speed Multiple: Displays the actual option switch setting
of the DSU speed multiple (56 or 64 Kb). The factory
default is 64 Kb multiples. Thi s field is a read only field and
may only be manually changed by the user (see Installation
on page 2-1). The factory default setting is 1536 Kb.
Clock: This field display the DSU clocking mode has been
manually optioned (Internal, External or Network) by the
user. The factory default is NETWORK.
DS0s: This field displays whether the unit has been configured for Alternate or Contiguous DS0 channel assignment.
The factory default is Contiguous.
Data Invert: This field displays whether the data invert
mode is ON or OFF. The factory default is OFF.
Control Lines: This field display whether or not the data
control lines are configured in the ON or OFF mode. The
factory default is OFF.
LAPS Operation 4-8
1558D APS CSU/DSU
Boot from: Displays the current setting of the APS
switches which determine the source of boot- time configuration mode. The choices are: Switches / ROM / RAM /
APSM. The factory default is SWITCHES.
must be configured to operate in either the normal mode or
in the transparent mode. The normal mode allows the slave
unit to respond to CSU loop commands and 54016 commands. The transparent mode disables all CSU response
functions of the slave unit.
Utilities Screen
The Utilities Screen (Figure 4 - 9) allows the user to set the
Date, Time, Location Header, and the Auto Log Off interval.
The following paragraphs describe these items.
Date: Selecting this field causes ‘Date’ to be prompted on
the bottom display line. The user may enter a new date in
the form MM/DD/YY. Pressing <enter> completes the
change.
Time: Selecting this field causes ’Time:’ to be prompt ed on
the bottom display line. The user may enter a new time in
the form HH:MM:SS. Pressing <enter> completes the
change.
Location Header: Not used in LAPS software applications
(1559 Manager only).
Auto Log Off: This field sets the time period for the Auto
Log Off feature, which logs the current user off the system
if there are no keys pressed for the period specified in this
field. When Auto Log Off occurs, the effect is the same as
selecting ‘Log Off’ or pressing <esc> while in the main
menu. The choices are: Never / 15 Minutes / 30 Minutes /
45 Minutes / 1 Hour. The factory default mode is NEVER.
Loopback Operations
The 1558D has several loops that can be initiated by the user
to assist in trouble shooting T1 transmission path problems
(see the Block Diagram in Figure 4 -10). It is important to
note that the types of loops that a 1558D unit can send or
respond too is dependent upon the man ual unit option settings (master/slave). It is also important to note that APS
service must be installed in pairs, one configured as the
master and the other as the slave. In addition, each APS pair
In most applications, APS service is provided by an IXC. In
these applications, the APS equipment located in the central
office will always be configured for Master/Normal
APS equipment located at the customer’s premise will be
configured for Slave/Normal
the factory configured for Slave/Normal operation.
The loop types that LAPS can initiate from the front pan el
SUPV port of a unit configured as a Master are:
• Near Payload Loop
• Near Line Loop
• Near Facility Loop
• Near Equipment Loop
• NPC Payload Loop (Transparent mode only)
• Far Payload
• Far Line
• CSU Loop
• NET Loop (Telco network interf ace)
The loop types that LAPS can initiate from the front pan el
SUPV port of a unit configured as a Slave are:
• Local Facility Loop
• Local Equipment Loop
Before performing loops and unloops, it is important to
understand that the user must carefully set up and select the
desired loopback. It is recommended that the user follow the
steps listed below when setting up a loopback.
1. From the Main Menu, select the Maintenance screen
2. From the Maintenance screen, decide which Path is to be
looped (A or B path).
3. If necessary, force the 1558D to use the Path (A or B)
that is not
to be looped.
4. Lock this Path (A or B). This prevents the 1558D from
switching the active path to the test path during testing.
The LAPS software and 1558D
hardware will not allow a user to
loop an active
tern to an active
line or apply a BERT pat-
line. Only a line shown
in the StandBy mode or Inhibited mode
can be looped or BERT tested.
5. Initiate the desired local/remote loop.
The following sections describe in detail how to perform
loops and unloops of the 1558D equipment. Note that all
loops and unloops are performed at the Maintenance screen.
The location of the various loops is depicted in the 1558D
Block Diagram shown in Figure 4-10. The remainder of this
chapter discusses these loops. The user should refer to the
block diagram mentioned earlier for a clearer understanding
of the loop that is being described by this material discu ssed
in the following paragraphs.
Near Payload Loop
Target the path (A or B) that you want to test by moving the
cursor highlight to the Target field and then, using the space
bar, toggle the field until it displays the SIDE that you want
to loop (Side A or Side B). After you have selected either
the A or B side as the target for testing, move the cursor
highlight to the Loop field and toggle the field, using the
space bar, until the field displays Near Payload. Then,
momentarily depress the <enter> key. The LAPS will initiate a payload loop of the selected target. After a few
moments, notice that the NEAR status field has changed
from Soft Inhibit or StandBy to PL LP. Also note that the
near 1558D front panel Loop LED indicator is on.
A payload loopback loops the incoming T1 signal back to
the network. The T1 signal is regenerated (both CRC and
signal level). In addition to looping the signal back to the
network, the signal is also passed to the 1558D DTE port.
Tx Clk
Ext Clk
Rx Clk
TM
DSR
CD
RTS
RD
SD
COM Bus
IN
COM Bus
OUT
Alarm
Contacts
(COM,
NO, NC)
APS
Select
Path A/B
V.35 Interface
Eq/V.54
Loop
Loop
Set/Reset
CPU
ROM
RAM
Performance History,
Alarms, Unit Address
SUPV
Port
A
B
Deframer
Fac/Local
PLB
Framer
Deframer
Fac/Local
PLB
Framer
Loop
Loop
Signal
Split
Line
Loop
+5 VDC
±12 VDC
NET A
BERT: QRSS,
1:8, 3:24, etc.
NET B
Line
Loop
Figure 4-10 1558D Block Diagram
Power
Supply
NET A
Bridge
Jack
Bridge
Jack
Bridge
Jack
Bridge
Jack
Receive
Transmit
NET A
AC Input, 110 VAC
NET B
Receive
Transmit
NET B
Jack
Jack
Jack
Jack
Line
Protection
Line
Protection
Line
Protection
Line
Protection
Rx
NET
A
RJ48
Tx
Rx
NET
B
RJ48
Tx
LAPS Operation 4-10
1558D APS CSU/DSU
To unloop the unit, move the cursor highlig ht to the Unloop
field and toggle the field, using the space bar, until Near
Payload is displayed. Then depress the <enter> key. The
LAPS will issue a payload unloop command. After a few
moments note that the NEAR status field changes from PL
LB to Soft Inhibit or Stan dBy. Also note that the LP LED
indicator on the 1558D turns off. The Payload loop is now
off.
Near Line Loop
Target the path (A or B) that you want to test by moving the
cursor highlight to the Target field and then, using the space
bar, toggle the field until it displays the to side that you want
to loop (Side A or Side B). After you have selected either
the A or B side as the target for testing, move the cursor
highlight to the Loop field and toggle the field, using the
space bar, until the field displays Near Line. Then momentarily depress the <enter> key. The LAPS will initiate a Near
Line loop of the selected target. After a few moments, notice
that the NEAR status field has changed from Soft Inhibit to
Line LP. Also note that the 1558D front panel Loop LED
indicator is on.
A Line loopback loops the incoming T1 signal from the
facility back to the network. Only the T1 signal level is
regenerated, not the CRC. In addition to looping the signal
back to the network, the signal is also passed to the 1558D
DTE port.
To unloop the unit, simp ly move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
Near Line is displayed. Then depress the <enter> key. The
LAPS will issue a line unloop command. After a few
moments note that the NEAR status field changes from Ln
Lp to Soft Inhibit or StandBy. Also note that the LP LED
indicator on the 1558D turns off. The Line loop is now off.
Near Facility Loop
Target the path (A or B) that you want to test by moving the
cursor highlight to the Target: field and then, using the spacebar, toggle the field until it displays the to sid e that you
want to loop (Side A or Side B). After you have selected
either the A or B side as the target for testing, move the cursor highlight to the Loop field and to ggle the field, usi ng th e
space bar, until the field displays Near Facility. Then
momentarily depress the <enter> key. The LAPS will initiate a Near Facility loop of the selected target. After a few
moments, notice that the NEAR status field has changed
from Soft Inhibit or StandBy to Fac LP. Also note that the
1558D front panel Loop LED indicator is on.
A facility loopback loops the outgoing T1 signa l back to the
1558D receive. The T1 signal level is regenerated and,
depending on the user option (regenerate CRC yes/no), the
CRC will or will not be regenerated. In addition to looping
the signal back to the 1558D re ceive, the signal is al so tran smitted to the network (see the block diagram in Figure 4-10).
To unloop the unit, sim ply move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
Near Facility is displayed. Then depress the <enter> key.
The LAPS will issue a line unloop command. After a few
moments note that the NEAR status field changes from Fac
Lp to Soft Inhibit or Standby. Also note that the LP indicator
on the unit turns off. The Line loop is now off.
Near Equipment Loop
A DTE equipment loopback loops the incoming T1 signal
coming into the DTE (Tx) port back to the DTE port (Rx).
Only the T1 signal level is regenerated, not the CRC. In
addition to looping the s ignal back to the DTE p ort, the signal is also transmitted to the network.
To initiate a CO Equ ipment Loop, first target the path (A or
B) that you want to test by moving the cursor highlight to
the Target: field and then, using the spacebar, toggle the
field until it displays the sid e that you want to loop (Side A
or Side B). After you have selected either the A or B side as
the target for testing, move the cursor highlight to the Loop
field and toggle the field, using the space bar, until the field
displays Near Equipment. Then momentarily depress the
<enter> key. The LAP S will respond by sending the following message to the user, “Warning! This loop disruptsactive service. Perform Loop? (Y/N).” If the user enters y
(yes), the system will initiate a DTE Equipment loop. After
a few moments, notice that the NEAR status fields for both
the A and B circuits has changed from Soft Inhibit or
StandBy to Eq Lp. Also note that the 1558D front panel
DTE Loop LED indicator is on. If the user enters N (no)
when prompted with the warning message, the LAPS system ignores the equipment loop command.
To unloop the unit, sim ply move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
Near Equipment is displayed. Then depress the <enter> key.
The LAPS will issue an Equipment unloop command. After
a few moments note that the NEAR status field changes
from Eq Lp to Soft Inhibit or StandBy. Also note that the LP
LED indicator on the 1558D turns off. The Equipment loop
is now off.
Far Payload
A Far Payload loopback is used to loop the far slave 1558D
unit from the master unit. At the far slave unit, the Payload
loopback loops the incoming T1 signal (RX) coming from
the network (NET A or NET B) port back to the network
(TX, NET A or NET B). Both the signal and CRC are
regenerated. In addition to looping the signal back to the
network, the signal is also transmitted to the DTE port.
To initiate a Far Payload loop, first target the path (A or B)
that you want to test by moving the curs or highlight to the
Target: field and then, using the spacebar, toggle the field
until it displays th e side that you want to loop (Side A or
Side B). After you have selected either the A or B side as
LAPS Operation 4-111558D APS CSU/DSU
the target for testing, move the cursor highlight to the Loop
field and toggle the field, using the space bar, until the field
displays Far Payload. Then momentarily depress the
<enter> key. The LAPS will respond by sending the appropriate loop command to the far slave unit. After a few
moments, notice that the FAR status field has changed from
Soft Inhibit or StandBy to PL LP. Also note that the 1558D
far slave 1558D Loop LED indicator is on.
To unloop the unit, simp ly move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
Far Payload is displayed. Then depress the <enter> key. The
LAPS will issue an unloop command . After a few moments
note that the FAR status field changes from PL LP to Soft
Inhibit or StandBy. Also note that the Loop LED indicator
on the far slave 1558D turns off. The Payload loop is now
off.
Far Li ne
A Far Line loopback is used to loop the far end slave 1558D
unit from the master unit. At the far end slave unit, the Far
Line loopback loops the incoming T1 signal (RX) coming
from the network (NET A or NET B) port back to the network (TX, NET A or NET B). Only the signal is regenerated by a Far Line loop. In addition to looping the signal
back to the network, the signal is also transmitted to the
DTE port.
To initiate a Far Line loop, first target the path (A or B) that
you want to test by moving the cursor highlight to the Target: field and then, using the spacebar, toggle the field until
it displays the side that you want to loop (Side A or Side B).
After you have selected either the A or B side as the target
for testing, move the cursor highlight to the Loop field and
toggle the field, using the space bar, until the field displays
Far Line. Then momentarily depress the <enter> key. The
LAPS will respond by sending the appropriate loop command to the far end slave unit. After a few moments, notice
that the FAR status field has changed from Soft Inhibit or
StandBy to Loop. Also note that the far slave 1558D Loop
LED indicator is on.
To unloop the unit, simp ly move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
Far Line is displayed. Then depress the <enter> key. The
LAPS will issue an unloop command . After a few moments
note that the FAR status field changes from Loop back to
Soft Inhibit or StandBy. Also note that the Loop LED indicator on the far slave 1558D turns off. The Line loop is now
off.
CSU Loop
The 1558D, when configured as a Slave unit with the CSU
mode Enabled, will respond to in dustry standard CSU loop
and unloop commands. A CSU loopback loops the incoming
T1 signal (RX) coming from the network (NET A or NET
B) back to the network (TX). Only the signal is regenerated
by a CSU loop. In addition to looping the signal back to the
network, the signal is also transmitted to the DTE port.
To initiate a CSU loop, first target the path (A or B) that you
want to test by moving the cursor highlight to the Target:
field and then, using the spacebar, toggle the field until it
displays the side that you want to loop (Side A or Side B).
After you have selected either the A or B side as the target
for testing, move the cursor highlight to the Loop field and
toggle the field, using the space bar, until the field displays
CSU. Then momentarily depress the <enter> key. The LAPS
will respond by sending the appropriate loop command to
the far end slave unit. After several seconds, notice that the
FAR status field has changed from Soft Inhibit or StandBy
to Loop. Also note that the far end slave 1558D front panel
Loop LED indicator is on.
To unloop the unit, sim ply move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
CSU is displayed. Then depress the <enter> key. The LAPS
will issue an unloop command. After several seconds, note
that the FAR status field changes from Loop to Soft Inhibit
or StandBy. Also note that the Loop LED indicator on the
far slave 1558D turns off. The CSU loop is now off.
NET Loop
The NET loop command is used to generate 5-bit patterns
towards the far end equipment. These patterns may be used
to loop a network interface device or a CSU. To initiate a 5bit NET pattern, first target the path (A or B) th at you want
to test by moving the cursor highlight to the Target: field
and then, using the spacebar, toggle the field until it displays
the side that you want to loop (Side A or Side B). After you
have selected either the A or B side as the target for testing,
move the cursor highlig ht to the Loop field and toggle the
field, using the space bar, until the field displays NET. Note
that when the NET command is selected, a user definable 5bit code field is also displayed [10000]. This 5-bit field can
be set to any combination of ones and zeros by moving the
cursor highlight to this field and then entering the desired
combination of ones and zeros at the message prompt.
The most common network interface loop up 5-bit pattern is
[11000]. The most common unloop 5-bit pattern for network
interface devices is [11100]. After selecting the 5-bit pattern, move the cursor back to the Loop field and press the
<enter> key. The LAPS responds by sending the selected
NET 5-bit code to the far end equipment for 5 seconds or
more.
To unloop the network interface device, simply move the
cursor to the Unloop field and toggle it with the spacebar,
until NET is displayed. Note th at when the NET command
is selected, a user definable 5-bit code is displayed [11100].
This field may be set to any combination of ones and zeros
by entering the desired combination. The most common network interface unloop command is [11100]. After pressing
<enter>, the LAPS will issue a NET unloop command for 5
LAPS Operation 4-12
1558D APS CSU/DSU
seconds or more, after which, the NET device should be
unlooped.
all Ones, all Zeros, user definable 3 - bit, and user definable
5 - bit.
NPC Payload Loop
The NPC Payload loopback is used to loop a far end slave
unit that is configured to operate in the transparent
(CSU Disabled option). In this mode the far end slave card
will not respond to any ESF CSU comma nds. Normally, this
application is used only by an IXC internal network protection applications. Note that a NPC Payload loop is functionally the same type as a Far Payload loopback.
A NPC Payload loopback is used to loop the slave 1558D
unit from the master unit. At th e far end slave unit, the NPC
Payload loopback loops the incoming T1 signal (RX) coming from the network (NET A or NET B) port and loops this
signal back to the network (TX). Both the signal and CRC is
regenerated. In addition to looping the signal back to the
network, the signal is also transmitted to the DTE port.
To initiate a NPC Payload loop, first target the path (A or B)
that you want to test by moving the cursor highlight to the
Target: field and then, using the spacebar, toggle the field
until it displays the side that you want to loop (Side A or
Side B). After you have selected either the A or B side as
the target for testing, move the cursor highlight to the Loop
field and toggle the field, using the space bar, until the field
displays NPC Payload. Then momentarily depress the
<enter> key. The LAPS will respond by sending the appropriate loop command to the far slave unit. After a few
moments, notice that the FAR status field has changed from
Soft Inhibit or StandBy to PL L P. Also note that the far end
1558D front panel Loop LED indicator is on.
To unloop the unit, simp ly move the cursor highlight to the
Unloop field and toggle the field, using the space bar, until
NPC Payload is displayed. Then depress the <enter> key.
The LAPS will issue an unloop command. After a few
moments note that the FAR status field changes from PL LP
to Soft Inhibit or StandBy. Also note that the Loop LED
indicator on the far slave 1558D turns off. The NPC Payload
loop is now off.
mode
BERT Testing
The user can perform BERT testing from a Master unit by
accessing the Maintenance screen. In the lower right hand
and left hand portions of the display are the command/toggle/information fields that are used for BERT testing. These
fields and their use are discussed below.
Pattern: Specifies which pattern will be transmitted during
test. When the 3 or 5-bit, user-d efined pattern is chosen , the
user may type in any patte rn of 1s and/ or 0s to be transmitted. Pressing <enter> with the cursor p ositi oned on th is field
will cause the pattern to be transmitted for the period of time
specified in ‘Test Time’. The choices are: QRSS, 1:8, 3:24,
If the 1558D DTE is configured for AMI operation, the test sets mus t be set to generate either a
511, 2047, or 1:7 pattern. If the 1558D is configured for B8ZS operation, any pattern may be
used (511, 2047, 1:7, QRSS, 3:24, etc.). When
sending a 1:7 pattern, though, some T1 test sets
inherently cause generation of a yellow alarm
condition.
Te s t T i m e : Defines the ru n- time of test pattern generation
and error accumulation and starts the test. Pressing <enter>
with the cursor positioned on this field will cause the
selected pattern to be transmitted for the s pecified period of
time. If the Maintenance menu is exited, pattern testing is
halted. The choices are: 15 Minutes, 30 Minutes, 45 Minutes, 1 Hour, and Continuous.
Runtime: Shows the amount of time elapsed since a timed
Pattern test began. Note that this field only appears on th e
screen when a test is running.
Near CRC Errors: A display-only field for viewing the
number of CRC errors which are received at the Near Target
receive path.
Far CRC Errors: A display-only field for viewing the
number of CRC errors which are received at the Far Target
receive.Far CRC Errors are only reported if the 1558D is
configured as a Master. Slave 1558D units do not report Far
CRC Errors.
Reset Errors: Pressing <enter> with the cursor positioned
on this field causes both the Near and Far CRC accumulators to be cleared (only if Master 1558D).
It is important to understand that the 1558D does not allow
testing (loop or BERT) on the active path. To perform testing on a given path the user must first configure the path to
the StandBy mode, Soft Inhibit mode or Manual Inhibit
mode. Once the path to be tested is in one of these modes,
the LAPS will allow the user to perform testing.
BERT testing can be performed either to loopbacks or
straight away to the far end. To perform a BERT test, the
user should follow the steps discussed below.
1. Select the path to be tested using the TARGET toggle
field.
2. Move the cursor highlight to the Pattern field and then,
using the spacebar, toggle the field until the desired user
pattern is display. The available patterns are; QRSS, 1:8,
3:24, all Ones, all Zeros, user definable 3-bit, and
user definable 5-bit.
3. Next, move the cursor highlight to the Test Time field
and then, using the spacebar, toggle the field to the
LAPS Operation 4-131558D APS CSU/DSU
desired test time. The choices are 15 minutes, 30 minutes, 1 Hour, 24 Hour s, and Continuo us.
4. Af ter performing Steps 1 - 3, move the curs or highlight
to either the Test Time or Pattern field and then momentarily depress the <enter> key. The system will immediately begin to generate the selected pattern on the
selected path for the selected time interval. Observing the
Near and Far end CRC errors counters will assist the user
in determining if the error problem is occurring in the
transmit or receive path.
The LAPS system cannot generate loops while a
BERT test is in process. Also, if the user exits the
‘Maintenance’ screen while a BERT is running,
the BERT stops.
While running the test, the user may reset the CRC error
counters by moving the cursor highlight to the Reset Errors
field and momentarily depress the <enter> key. This will
reset the Near and Far CRC error counters to zero. Performing an error reset does not stop the BERT test in progress.
The user may stop the BERT test at any time by simply
moving the cursor highlight to either the Pattern or Test
Time command fields and then depress the <enter> key. The
system responds by turning off the Runtime clock disp lay.
To restart the test, simply depress the <enter> key again.
The system responds by applying the selected BERT pattern
and restarting the Runtime clock display.
LAPS Operation 4-14
1558D APS CSU/DSU
Index
I-1
Numerics
1557 ADDRESS SETTINGS
B
Bipolar Violations
3-1
C
Circuit List Screens
Circuit ID 4-3
Far 4-4
Near 4-4
Pos 4-3
State 4-3
Circuits in Alarms
Circuits in T est
Configuration Screen
Booting 4-9
Circuit A/B 4-8
Consecutive SES 4-8
DSX Level 4-8
Errored Seconds 4-8
Line Availability Timer 4-8
LOS/LOF State 4-8
Net End 4-8
Revert 4-8
Revision 4-8
Service Status 4-8
Shelf/Position 4-8
Connections
Alarm 2-2
Chassis Ground 2-1
NET A 3-9
REAR PANEL 2-1, 3-7
T - View Bus 2-2
T - View IN and OUT 3-9
T1 2-2
4-3
4-3
4-3
4-7
D
Data Link Loop Backs
3-1
2-3
F
FCC Requirements
FRONT PANEL INDICATORS
1-2
L
Location Header
Loss of Frame
Loss of Signal
4-2
3-1
3-1
M
Main Menu
Maintenance Screen
Clear Alarms 4-6
CRC Errors, Far 4-7, 4-13
CRC Errors, Near 4-7, 4-13
Force 4-6
Lock 4-6
Loop 4-6
Pattern 4-7
Reset Errors 4-7, 4-13
Runtime 4-7, 4-13
Target 4-6
Test Time 4-7, 4-13
Unlock 4-6
Unloop 4-7