RAD Data comm ASM-20 User Manual
Installation and Operation Manual
2
S
S
ASM-
ynchronous/Asynchronous
hort Range Modem
0
ASM-20
Synchronous/Asynchronous Short Range Modem
Installation and Operation Manual
Notice
This manual contains information that is proprietary to RAD Data Communications Ltd. ("RAD"). No
part of this publication may be reproduced in any form whatsoever without prior written approval by
RAD Data Communications.
Right, title and interest, all information, copyrights, patents, know-how, trade secrets and other
intellectual property or other proprietary rights relating to this manual and to the ASM-20 and any
software components contained therein are proprietary products of RAD protected under international
copyright law and shall be and remain solely with RAD.
ASM-20 is a registered trademark of RAD. No right, license, or interest to such trademark is granted
hereunder, and you agree that no such right, license, or interest shall be asserted by you with respect
to such trademark.
You shall not copy, reverse compile or reverse assemble all or any portion of the Manual or the
ASM-20. You are prohibited from, and shall not, directly or indirectly, develop, market, distribute,
license, or sell any product that supports substantially similar functionality as the ASM-20, based on or
derived in any way from the ASM-20. Your undertaking in this paragraph shall survive the termination
of this Agreement.
This Agreement is effective upon your opening of the ASM-20 package and shall continue until
terminated. RAD may terminate this Agreement upon the breach by you of any term hereof. Upon
such termination by RAD, you agree to return to RAD the ASM-20 and all copies and portions thereof.
For further information contact RAD at the address below or contact your local distributor.
International Headquarters
RAD Data Communications Ltd.
24 Raoul Wallenberg St.
Tel Aviv 69719 Israel
Tel: 972-3-6458181
Fax: 972-3-6498250
E-mail: market@rad.com
© 1989–2005 RAD Data Communications Ltd. Publication No. 601-200-09/05
North America Headquarters
RAD Data Communications Inc.
900 Corporate Drive
Mahwah, NJ 07430 USA
Tel: (201) 529-1100, Toll free: 1-800-444-7234
Fax: (201) 529-5777
E-mail: market@radusa.com
Limited Warranty
RAD warrants to DISTRIBUTOR that the hardware in the ASM-20 to be delivered hereunder shall be
free of defects in material and workmanship under normal use and service for a period of twelve (12)
months following the date of shipment to DISTRIBUTOR.
If, during the warranty period, any component part of the equipment becomes defective by reason of
material or workmanship, and DISTRIBUTOR immediately notifies RAD of such defect, RAD shall have
the option to choose the appropriate corrective action: a) supply a replacement part, or b) request
return of equipment to its plant for repair, or c) perform necessary repair at the equipment's location.
In the event that RAD requests the return of equipment, each party shall pay one-way shipping costs.
RAD shall be released from all obligations under its warranty in the event that the equipment has been
subjected to misuse, neglect, accident or improper installation, or if repairs or modifications were
made by persons other than RAD's own authorized service personnel, unless such repairs by others
were made with the written consent of RAD.
The above warranty is in lieu of all other warranties, expressed or implied. There are no warranties
which extend beyond the face hereof, including, but not limited to, warranties of merchantability and
fitness for a particular purpose, and in no event shall RAD be liable for consequential damages.
RAD shall not be liable to any person for any special or indirect damages, including, but not limited to,
lost profits from any cause whatsoever arising from or in any way connected with the manufacture,
sale, handling, repair, maintenance or use of the ASM-20, and in no event shall RAD's liability exceed
the purchase price of the ASM-20.
DISTRIBUTOR shall be responsible to its customers for any and all warranties which it makes relating
to ASM-20 and for ensuring that replacements and other adjustments required in connection with the
said warranties are satisfactory.
Software components in the ASM-20 are provided "as is" and without warranty of any kind. RAD
disclaims all warranties including the implied warranties of merchantability and fitness for a particular
purpose. RAD shall not be liable for any loss of use, interruption of business or indirect, special,
incidental or consequential damages of any kind. In spite of the above RAD shall do its best to provide
error-free software products and shall offer free Software updates during the warranty period under
this Agreement.
RAD's cumulative liability to you or any other party for any loss or damages resulting from any claims,
demands, or actions arising out of or relating to this Agreement and the ASM-20 shall not exceed the sum
paid to RAD for the purchase of the ASM-20. In no event shall RAD be liable for any indirect, incidental,
consequential, special, or exemplary damages or lost profits, even if RAD has been advised of the
possibility of such damages.
This Agreement shall be construed and governed in accordance with the laws of the State of Israel.
General Safety Instructions
The following instructions serve as a general guide for the safe installation and operation of
telecommunications products. Additional instructions, if applicable, are included inside the manual.
Safety Symbols
This symbol may appear on the equipment or in the text. It indicates
potential safety hazards regarding product operation or maintenance to
operator or service personnel.
Warning
Danger of electric shock! Avoid any contact with the marked surface while
the product is energized or connected to outdoor telecommunication lines.
.
Warning
Protective earth: the marked lug or terminal should be connected to the building
protective earth bus.
Some products may be equipped with a laser diode. In such cases, a label
with the laser class and other warnings as applicable will be attached near
the optical transmitter. The laser warning symbol may be also attached.
Please observe the following precautions:
• Before turning on the equipment, make sure that the fiber optic cable is
intact and is connected to the transmitter.
• Do not attempt to adjust the laser drive current.
• Do not use broken or unterminated fiber-optic cables/connectors or look
straight at the laser beam.
• The use of optical devices with the equipment will increase eye hazard.
• Use of controls, adjustments or performing procedures other than those
specified herein, may result in hazardous radiation exposure.
ATTENTION: The laser beam may be invisible!
In some cases, the users may insert their own SFP laser transceivers into the product. Users are alerted
that RAD cannot be held responsible for any damage that may result if non-compliant transceivers are
used. In particular, users are warned to use only agency approved products that comply with the local
laser safety regulations for Class 1 laser products.
Always observe standard safety precautions during installation, operation and maintenance of this
product. Only qualified and authorized service personnel should carry out adjustment, maintenance or
repairs to this product. No installation, adjustment, maintenance or repairs should be performed by
either the operator or the user.
Handling Energized Products
General Safety Practices
Do not touch or tamper with the power supply when the power cord is connected. Line voltages may be
present inside certain products even when the power switch (if installed) is in the OFF position or a fuse is
blown. For DC-powered products, although the voltages levels are usually not hazardous, energy hazards
may still exist.
Before working on equipment connected to power lines or telecommunication lines, remove jewelry or any
other metallic object that may come into contact with energized parts.
Unless otherwise specified, all products are intended to be grounded during normal use. Grounding is
provided by connecting the mains plug to a wall socket with a protective earth terminal. If an earth lug is
provided on the product, it should be connected to the protective earth at all times, by a wire with a
diameter of 18 AWG or wider. Rack-mounted equipment should be mounted only in earthed racks and
cabinets.
Always make the ground connection first and disconnect it last. Do not connect telecommunication cables
to ungrounded equipment. Make sure that all other cables are disconnected before disconnecting the
ground.
Connection of AC Mains
Make sure that the electrical installation complies with local codes.
Always connect the AC plug to a wall socket with a protective ground.
The maximum permissible current capability of the branch distribution circuit that supplies power to the
product is 16A. The circuit breaker in the building installation should have high breaking capacity and must
operate at short-circuit current exceeding 35A.
Always connect the power cord first to the equipment and then to the wall socket. If a power switch is
provided in the equipment, set it to the OFF position. If the power cord cannot be readily disconnected in
case of emergency, make sure that a readily accessible circuit breaker or emergency switch is installed in the
building installation.
In cases when the power distribution system is IT type, the switch must disconnect both poles
simultaneously.
Connection of DC Mains
Unless otherwise specified in the manual, the DC input to the equipment is floating in reference to the ground.
Any single pole can be externally grounded.
Due to the high current capability of DC mains systems, care should be taken when connecting the DC supply
to avoid short-circuits and fire hazards.
DC units should be installed in a restricted access area, i.e. an area where access is authorized only to
qualified service and maintenance personnel.
Make sure that the DC supply is electrically isolated from any AC source and that the installation complies
with the local codes.
The maximum permissible current capability of the branch distribution circuit that supplies power to the
product is 16A. The circuit breaker in the building installation should have high breaking capacity and must
operate at short-circuit current exceeding 35A.
Before connecting the DC supply wires, ensure that power is removed from the DC circuit. Locate the
circuit breaker of the panel board that services the equipment and switch it to the OFF position. When
connecting the DC supply wires, first connect the ground wire to the corresponding terminal, then the
positive pole and last the negative pole. Switch the circuit breaker back to the ON position.
A readily accessible disconnect device that is suitably rated and approved should be incorporated in the
building installation.
If the DC mains are floating, the switch must disconnect both poles simultaneously.
Connection of Data and Telecommunications Cables
Data and telecommunication interfaces are classified according to their safety status.
The following table lists the status of several standard interfaces. If the status of a given port differs from
the standard one, a notice will be given in the manual.
Ports Safety Status
V.11, V.28, V.35, V.36, RS-530,
X.21, 10 BaseT, 100 BaseT,
Unbalanced E1, E2, E3, STM, DS-2,
DS-3, S-Interface ISDN, Analog voice
E&M
xDSL (without feeding voltage),
Balanced E1, T1, Sub E1/T1
FXS (Foreign Exchange Subscriber) TNV-2 Telecommunication Network Voltage-2:
FXO (Foreign Exchange Office), xDSL
(with feeding voltage), U-Interface
ISDN
SELV Safety Extra Low Voltage:
Ports which do not present a safety hazard. Usually
up to 30 VAC or 60 VDC.
TNV-1 Telecommunication Network Voltage-1:
Ports whose normal operating voltage is within the
limits of SELV, on which overvoltages from
telecommunications networks are possible.
Ports whose normal operating voltage exceeds the
limits of SELV (usually up to 120 VDC or telephone
ringing voltages), on which overvoltages from
telecommunication networks are not possible. These
ports are not permitted to be directly connected to
external telephone and data lines.
TNV-3 Telecommunication Network Voltage-3:
Ports whose normal operating voltage exceeds the
limits of SELV (usually up to 120 VDC or telephone
ringing voltages), on which overvoltages from
telecommunication networks are possible.
Always connect a given port to a port of the same safety status. If in doubt, seek the assistance of a
qualified safety engineer.
Always make sure that the equipment is grounded before connecting telecommunication cables. Do
not disconnect the ground connection before disconnecting all telecommunications cables.
Some SELV and non-SELV circuits use the same connectors. Use caution when connecting cables.
Extra caution should be exercised during thunderstorms.
When using shielded or coaxial cables, verify that there is a good ground connection at both ends. The
earthing and bonding of the ground connections should comply with the local codes.
The telecommunication wiring in the building may be damaged or present a fire hazard in case of
contact between exposed external wires and the AC power lines. In order to reduce the risk, there are
restrictions on the diameter of wires in the telecom cables, between the equipment and the mating
connectors.
A
n
Caution
To reduce the risk of fire, use only No. 26 AWG or larger telecommunication line cords.
ttentio
Pour réduire les risques s’incendie, utiliser seulement des conducteurs de
télécommunications 26 AWG ou de section supérieure.
Some ports are suitable for connection to intra-building or non-exposed wiring or cabling only. In such
cases, a notice will be given in the installation instructions.
Do not attempt to tamper with any carrier-provided equipment or connection hardware.
Electromagnetic Compatibility (EMC)
The equipment is designed and approved to comply with the electromagnetic regulations of major
regulatory bodies. The following instructions may enhance the performance of the equipment and will
provide better protection against excessive emission and better immunity against disturbances.
A good earth connection is essential. When installing the equipment in a rack, make sure to remove all
traces of paint from the mounting points. Use suitable lock-washers and torque. If an external
grounding lug is provided, connect it to the earth bus using braided wire as short as possible.
The equipment is designed to comply with EMC requirements when connecting it with unshielded
twisted pair (UTP) cables. However, the use of shielded wires is always recommended, especially for
high-rate data. In some cases, when unshielded wires are used, ferrite cores should be installed on
certain cables. In such cases, special instructions are provided in the manual.
Disconnect all wires which are not in permanent use, such as cables used for one-time configuration.
The compliance of the equipment with the regulations for conducted emission on the data lines is
dependent on the cable quality. The emission is tested for UTP with 80 dB longitudinal conversion loss
(LCL).
Unless otherwise specified or described in the manual, TNV-1 and TNV-3 ports provide secondary
protection against surges on the data lines. Primary protectors should be provided in the building
installation.
The equipment is designed to provide adequate protection against electro-static discharge (ESD).
However, it is good working practice to use caution when connecting cables terminated with plastic
connectors (without a grounded metal hood, such as flat cables) to sensitive data lines. Before
connecting such cables, discharge yourself by touching earth ground or wear an ESD preventive wrist
strap.
FCC-15 User Information
This equipment has been tested and found to comply with the limits of the Class A digital device,
pursuant to Part 15 of the 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 Installation and Operation manual, may cause harmful interference to the radio
communications. Operation of this equipment in a residential area is likely to cause harmful
interference in which case the user will be required to correct the interference at his own expense.
A
A
Canadian Emission Requirements
This Class A digital apparatus meets all the requirements of the Canadian Interference-Causing
Equipment Regulation.
Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel
brouilleur du Canada.
Warning per EN 55022 (CISPR-22)
Warning
vertissement
chtung
This is a class A product. In a domestic environment, this product may cause
radio interference, in which case the user will be required to take adequate
measures.
Cet appareil est un appareil de Classe A. Dans un environnement résidentiel, cet
appareil peut provoquer des brouillages radioélectriques. Dans ces cas, il peut
être demandé à l’utilisateur de prendre les mesures appropriées.
Dieses ist ein Gerät der Funkstörgrenzwertklasse A. In Wohnbereichen können
bei Betrieb dieses Gerätes Rundfunkströrungen auftreten, in welchen Fällen der
Benutzer für entsprechende Gegenmaßnahmen verantwortlich ist.
Declaration of Conformity
Manufacturer's Name: RAD Data Communications Ltd.
Manufacturer's Address: 24 Raoul Wallenberg St.
Tel Aviv 69719
Israel
declares that the product:
Product Name: ASM-20
conforms to the following standard(s) or other normative document(s):
EMC: EN 55022: 1998 Information technology equipment, radio disturbance
characteristics, limits and methods of measurement.
EN 50024: 1998 Information technology equipment, immunity characteristics,
limits and methods of measurement.
Safety: EN 60950: 2000 Safety of information technology equipment.
Supplementary Information:
The product herewith complies with the requirements of the EMC Directive 89/336/EEC, the Low
Voltage Directive 73/23/EEC and the R&TTE Directive 99/5/EC for wired equipment. The product was
tested in a typical configuration.
Tel Aviv, 22 January, 2003
Haim Karshen
VP Quality
European Contact: RAD Data Communications GmbH, Otto-Hahn-Str. 28-30, 85521
Ottobrunn-Riemerling, Germany
Note
Quick Start Guide
If you are familiar with ASM-20, use this guide to prepare it for operation.
Perform the following steps for both the local and the remote units.
1. Disconnect all cables from the units.
2. Open the units.
3. Adjust the jumpers. See Chapter 2, Installation and Setup.
Make sure that there is only one clock source in the application: one modem INT or
EXT and the other modem RCV (LBT).
4. Configure the DTE parameters. See Chapter 2, Installation and Setup.
5. Configure the line parameters. See Chapter 2, Installation and Setup.
6. Close the units.
7. Connect the units to the DTEs.
8. Turn on the units.
9. Connect the units to the line. The units should begin operating within a few
seconds.
1
Quick Start Guide ASM-20 Installation and Operation Manual
2
Contents
Chapter 1. Introduction
1.1 Overview..................................................................................................................... 1-1
Applications.......................................................................................................................... 1-1
Features................................................................................................................................ 1-2
Options ................................................................................................................................1-2
1.2 Physical Description..................................................................................................... 1-3
Front Panel........................................................................................................................... 1-3
LEDs..................................................................................................................................... 1-3
Jumpers................................................................................................................................ 1-3
Rear Panel ............................................................................................................................ 1-3
1.3 Functional Description................................................................................................. 1-4
Encoder................................................................................................................................1-4
Modulation Timing ............................................................................................................... 1-5
XMT Level (optional)............................................................................................................. 1-5
Receiver ...............................................................................................................................1-5
Remote Power Failure (RPF)..................................................................................................1-5
V.54 Diagnostics................................................................................................................... 1-5
Async to Sync Converter ....................................................................................................... 1-5
X.21 Buffer (for X.21 interface).............................................................................................. 1-6
Test Pattern Generator and Receiver .....................................................................................1-6
X.21 External Clock Buffer Option.........................................................................................1-6
G.703 DTE Interface.............................................................................................................1-6
1.4 Technical Specifications............................................................................................... 1-7
Chapter 2. Installation and Setup
2.1 Introduction................................................................................................................. 2-1
2.2 Site Preparation and Prerequisites................................................................................ 2-1
2.3 Package Contents ........................................................................................................2-1
2.4 Equipment Needed ..................................................................................................... 2-2
2.5 Setting Internal Jumpers and Switches.......................................................................... 2-2
2.6 Connecting the Cables................................................................................................. 2-6
Strap Selection...................................................................................................................... 2-7
Power Connection................................................................................................................ 2-7
Chapter 3. Operation
3.1 Power On.................................................................................................................... 3-1
3.2 Controls and Indicators................................................................................................ 3-1
3.3 Operation.................................................................................................................... 3-4
Test Activation ...................................................................................................................... 3-4
Operational Jumper and Switch Changes ..............................................................................3-4
3.4 Power Off.................................................................................................................... 3-4
Chapter 4. Troubleshooting and Diagnostics
4.1 Loop Test Procedure.................................................................................................... 4-1
4.2 Bit Error Rate Tester (BERT).......................................................................................... 4-1
ASM-20 Installation and Operation Manual i
Table of Contents
4.3 Modem Self Test.......................................................................................................... 4-3
4.4 Local Test - Analog Loopback ...................................................................................... 4-3
4.5 Communication Link Tests........................................................................................... 4-4
Remote Digital Loopback...................................................................................................... 4-4
Local Digital Loopback..........................................................................................................4-5
4.6 Frequently Asked Questions ........................................................................................ 4-6
4.7 Technical Support........................................................................................................ 4-7
Chapter 5. Card-Cage Version
5.1 ASM-MN-214 Card Cage............................................................................................. 5-1
5.2 ASM-20/R Card Version............................................................................................... 5-3
5.3 Power Supply .............................................................................................................. 5-4
AC Supply (100, 115 or 230 VAC).........................................................................................5-4
DC Supply (-48 VDC) ........................................................................................................... 5-4
Power Supply with Redundancy............................................................................................5-4
5.4 Installation ................................................................................................................... 5-6
Appendix A. Ethernet Interface
Appendix B. IR-G.703 Codirectional Interface (64 kbps)
Appendix C. IR-X.21B Interface Module
Appendix D. DTE Interface Connectors
Appendix E. Connection to RS-422
Appendix F. Unit Case Assembly
ASM-20 Installation and Operation Manual
Applications
Chapter 1 Introduction
1.1 Overview
The ASM-20 short range modem operates synchronously or asynchronously at
full-or half-duplex, over unconditioned lines. ASM-20 has a range of up to 23 km
(14 mi) and operates at selectable data rates from 19.2 kbps to 256 kbps.
ASM-20 uses conditioned diphase modulation (EUROCOM Std. D1) to provide
immunity from background noise, eliminate normal line distortion, and enable
efficient transmission and reception of serial data over a twisted pair cable.
Transmit timing is provided internally, or derived externally from the data terminal
or regenerated from the receive signal.
Receive timing is regenerated from the data.
HOST
DTE
The following diagrams illustrate ASM-20 in a variety of applications:
• Point-to-point
• Modem link
• Tail-end for digital networks.
4-WIRE
Up to 23 km
RAD RAD
ASM-20 ASM-20
Figure 1-1. Point-to-point Application
19.2 - 256 kbs
Ter m in a l
Overview 1-1
Chapter 1 Introduction ASM-20 Installation and Operation Manual
RAD
ASM-20
RCV CLK
Ter m in a l
RAD
ASM-20
RCV CLK
RAD
ASM-20
EXT CLK
G.703
DIGITAL
SERVICE
NETWORK
RAD
ASM-20
EXT CLK
DTE
Figure 1-2. G.703 Modem Link Application
Features
Options
RAD
ASM-20
RAD
ASM-20
G.703 or
X.21/RS-530/V.24
or V.35 or ETH
DTE
Figure 1-3. Tail-end for Digital Network Application
ASM-20 features V.54 diagnostic capabilities for performing local analog loopback
and local and remote digital loopback. The operator at either end of the line may
test both modems and the line when in digital loopback mode. The loopback is
controlled by either front panel push buttons or via the DTE interface.
The following DTE interface options are available:
• V.24/RS-232(up to 64 kbps)
• V.35
• X.21
• RS-530
• V.36
• G.703 (64 kbps co-directional)
1-2 Overview 02-Aug-2005 10:47
ASM-20 Installation and Operation Manual Chapter 1 Introduction
• Built-in Ethernet bridge.
Connection to an RS-449/V.36 interface is accomplished via the RS-530 interface
(see Appendix A, Ethernet Interface). ASM-20 incorporates a built-in Bit Error Rate
Tester (BERT). The internal BERT allows complete testing of both modems and the
line without external test equipment. A front panel switch generates a pseudorandom test pattern (511-bit, according to ITU/V.52) for testing end-to-end
connectivity. The ERROR LED will flash when a bit error is encountered.
1.2 Physical Description
ASM-20 is available as a desk-top unit or a rack-mountable card for a 19" rack.
The rack can carry up to 14 ASM-20 cards which provide a 25-pin
D-type connection to the digital interface. Optional interface adapters for V.35,
X.21, G703 and ETH are available. The ASM-20/R card can detect and indicate
power failure on the remote ASM-20 standalone unit. The RPF LED will light up if
remote power failure occurs.
Front Panel
LEDs
Jumpers
Figure 1-4 shows a general view of ASM-20.
Figure 1-4. ASM-20
All controls (push button and LED indicators are located on the ASM-20 front
panel (see Figure 1-4). A description of the front panel can be found in Controls
and Indicators in Chapter 3.
A description of the jumpers can be found in Setting Internal Jumpers and Switches
in Chapter 2. See Table 2-1 and Figure 2-3.
Rear Panel
Figure 1-5. ASM-20 Rear Panel with V.35 Interface
Physical Description 1-3
Chapter 1 Introduction ASM-20 Installation and Operation Manual
shows an example of an ASM-20 rear panel. A description of the rear panel can
be found in Electrical Installation in Chapter 2.
The line and interface connectors are located on the rear panel of ASM-20 (see
Figure 1-5).
DTE
100-115 VAC
-0.2A T 250V
~230 V/ 0.1A T 250V
GNDRCVXMT
Figure 1-5. ASM-20 Rear Panel with V.35 Interface
1.3 Functional Description
This section contains functional descriptions of the circuit blocks in ASM-20,
primarily those circuits which are required for configuring the modem (see
Figure 1-6).
Figure 1-6. ASM-20 Block Diagram
Encoder
The encoder receives data from the DTE, then modulates the data using the CDD
“conditional diphase modulation” technique.
• 4-wire full-duplex
• 4-wire half-duplex.
1-4 Functional Description 02-Aug-2005 10:47
ASM-20 Installation and Operation Manual Chapter 1 Introduction
Modulation Timing
This circuit supplies the transmit clock to the encoder. Three clock sources are
available:
• Internal oscillator
• External from the DTE
• Loop clock derived from the receive signal.
Setting the XMT CLK jumper determines the timing option. See Setting Internal
Jumpers and Switches in Chapter 2 for more information.
XMT Level (optional)
Two options are available for the XMT level (signal level): 0 and -6 dBm. XMT level
is controlled by the XMT LVL jumper. See Setting Internal Jumpers and Switches in
Chapter 2 for more information on the XMT LVL jumper.
An optional output filter to the line is available. This filter can be ordered in
compliance with British Telecom and other PTT requirements.
Receiver
The receiver comprises several circuits as shown in the block diagram
(see Figure 1-6):
• The RECEIVE FILTER removes all the out-band frequencies.
• The AUTOMATIC EQUALIZER comprises several equalizers which are
activated according to baud rate.
• The digital AGC automatically compensates for the attenuation of the line.
Remote Power Failure (RPF)
The Remote Power Failure feature allows the user at a central location to detect a
power failure in a remote modem. The remote power failure feature can only be
configured when the ASM-20/SA standalone unit (remote) operates opposite the
rack-mounted card ASM-20/R (central). When a power failure occurs, ASM-20/SA
transmits a special tone which is detected by ASM-20/R and causes the ERR/RPF
LED to light up. A special push button located on the front panel of ASM-20/R
allows the user to reset the RPF LED. The RPF jumper in the standalone unit
enables or disables the feature. The RPF feature should be disabled for multipoint
applications.
V.54 Diagnostics
V.54 loops are activated either by manual front panel push buttons or via the DTE
interface. The push buttons and the DTE interface can be enabled or disabled
separately by the SWITCH EN, ALB DTE, RLB DTE jumpers respectively. See
Setting Internal Jumpers and Switches in Chapter 2, for more information.
Async to Sync Converter
ASM-20 has an internal asynchronous to synchronous converter and synchronous
to asynchronous converter (used for asynchronous data).
Functional Description 1-5
Chapter 1 Introduction ASM-20 Installation and Operation Manual
A synchronous transmission is provided by internal conversion from asynchronous
to synchronous mode in compliance with ITU V.22 bis. In this standard, the
modem compensates for frequency deviation between the modem and the DTE
by adjusting the length of the stop bit of the async character. If the modem’s
frequency is lower than the DTE, the local converter deletes one stop bit in every
four (25%) or eight (12.5%) characters. The remote converter will add a shorter
stop bit (shorter by 12.5% or 25%) before sending the data to the remote DTE.
A suitable operation of the ASYNC to SYNC converter is selected by adjusting the
proper character length and frequency deviation setting (dip switch bank), see
Figure 2-3 and Table 2-2.
X.21 Buffer (for X.21 interface)
To allow tail-end connection on an X-21 interface, a buffer is provided on received
data. When ASM-20 is used in external clock configuration, set jumper JP2 to EXT.
When internal or receive clock configuration is used, set the jumper to the
opposite side. See Appendix C, IR-X.21B Interface Module for more information.
Test Pattern Generator and Receiver
This feature allows for easy and quick testing of the local modem as well as the
communication link. When the PATT button on the front panel is activated, the
circuit sends and checks a standard 511-bit pseudo random pattern. If errors are
encountered, the ERROR LED remains ON or blinks.
The test can be carried out in local analog loopback, in remote digital loopback or
in normal point-to-point operation opposite a remote ASM-20 modem. Press the
PATT push button on the remote unit or connect a Bit Error Rate Tester which uses
the standard 511-bit pattern.
X.21 External Clock Buffer Option
Available with X.21 interface model only. See Appendix C, IR-X.21B Interface
Module for more information.
G.703 DTE Interface
Available with G.703 interface model only. See Appendix B, IR-G.703
Codirectional Interface (64 kbps) for more information.
1-6 Functional Description 02-Aug-2005 10:47
ASM-20 Installation and Operation Manual Chapter 1 Introduction
1.4 Technical Specifications
Transmission Line
Digital Interface
Type
Range
Level
Transmit Impedance
Receive Impedance
Return Loss
Carrier
Modulation
Type
Unloaded twisted pair 19 to 26 AWG
See Table 1-1
Strap-selectable to 0 dBm or -6 dBm
150Ω or LOW (strap selectable)
150Ω or HIGH (strap selectable)
Greater than 15 dB
Controlled by RTS or constantly ON
Conditional diphase European Std. D1
V.24/RS-232 via 25-pin D-type, (up to 64 kbps
only), female connector
V.35 via 34-pin female connector
X.21 via 15-pin D-type female connector
RS-530 (RS-422) via 25-pin D-type female
connector
V.36 (RS-449) via 37-pin female connector using
mechanical cable adapter provided with the
product
G.703 Codirectional (64 kbps) via terminal block
or RJ-45
Built-in Ethernet bridge via RJ-45 connector or
BNC
Data Rates - selectable
RTS/CTS Delay
Length of Word
Stop Bits
Sync:
19.2, 32, 48, 56, 64, 72, 96, 112, 128, 144, 192,
256 kbps
Async:
19.2, 28.8, 38.4, 57.6, 115.2 kbps
Switch selectable to:
- 0 ms
- 9 ms
- 70 ms
8, 9, 10, 11
1, 1.5, 2
Technical Specifications 1-7
Chapter 1 Introduction ASM-20 Installation and Operation Manual
Diagnostics
(Complies with the
V.54 Standard)
Timing Elements
Indicators
Digital Loopback
Analog Loopback
Pattern
Receive Clock
Transmit Clock
Power
Request to Send
Transmit Data
Receive Data
Local (DIG), activated by a manual switch
Remote (REM), activated by a manual switch or
by a control signal from the DTE interface
connector
Local (ANA), activated by a manual switch or by a
control signal from the DTE interface connector
Test pattern activated by manual switch
Derived from the receive signal
Derived from 3 alternative sources:
Internal oscillator
External from the DTE
Loop clock derived from the receive signal
PWR (green)
RTS (yellow)
TD (yellow)
RD (yellow)
Electrical
Physical
Environment
Data Carrier Detect
Test
Bit errors
Power Supply
ASM-20 Modem
ASM-20-R Card
Temperature
Humidity
DCD (yellow)
TEST (red)
Err (yellow)
115 or 230 V (± 10%)
47 to 63 Hz; 5W
-48 VDC or 24 VDC
Height: 44 mm/ 1.7 in
Width: 215 mm/ 8.5 in
Depth: 243 mm/ 9.6 in
Weight: 1.1 kg / 2.4 lb
Dimensions: Fits ASM-MN-214 modem rack
Weight: 290 gm / 10.1 oz
0° - 50°C / 32° - 122°F
Up to 90%, non-condensing
1-8 Technical Specifications 02-Aug-2005 10:47
ASM-20 Installation and Operation Manual Chapter 1 Introduction
Table 0-1 Approximate Range
Baud
Rate
19 AWG
(0.8 mm)
22 AWG
(0.6 mm)
24 AWG
(0.5 mm)
26 AWG
(0.4 mm)
kbps km miles km miles km miles km miles
256 3.75 2.3 2.85 1.75 2.25 1.4 1.9 1.2
192 6.0 3.7 4.5 2.8 3.5 2.2 2.7 1.7
144 10.6 6.6 6.75 4.2 4.5 2.8 3.4 2.1
128 12.4 7.7 7.3 4.5 5.0 3.1 3.6 2.2
115.2* 12.8 7.8 7.65 4.75 5.25 3.3 3.8 2.5
112 12.8 8.0 8.0 5.0 5.5 3.4 4.0 2.5
96 13.0 8.1 8.3 5.15 6.0 3.7 4.15 2.6
72 15.0 9.3 9.4 5.8 6.25 3.9 4.3 2.65
64 17.6 11.0 11.0 6.8 7.5 4.6 5.3 3.3
57.6* 18.8 11.7 11.75 7.3 8.0 5.0 5.6 3.5
56 18.8 11.7 11.75 7.3 8.0 5.0 5.6 3.5
48 19.4 12.0 12.2 7.6 8.25 5.2 5.8 3.6
38.4* 20 12.5 12.5 7.8 8.5 5.3 6.0 3.7
32 20.5 12.75 12.85 8.0 8.75 5.4 6.2 3.85
28.8* 20.5 12.75 12.85 8.0 8.75 5.4 6.2 3.85
19.2** 23.0 14.0 14.0 8.7 9.75 6.0 7.0 4.3
* Async baud rate
** Sync/Async baud rate
Technical Specifications 1-9
Chapter 1 Introduction ASM-20 Installation and Operation Manual
1-10 Technical Specifications 02-Aug-2005 10:47
Loading...