CUSTOMER
SUPPORT
INFORMATION
Order toll-free in the U.S.: Call 877-877-BBOX (outside U.S. call 724-746-5500)
FREE technical support 24 hours a day, 7 days a week: Call 724-746-5500 or fax 724-746-0746
Mailing address: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com • E-mail: info@blackbox.com
NOVEMBER 2001
ME0006A-10BT
2-Wire Short-Range DSL Line Driver
(HDSL with 10BASE-T)
1
FCC AND IC RFI STATEMENTS/CE NOTICE
FEDERAL COMMUNICATIONS COMMISSION
AND
INDUSTRY CANADA
RADIO FREQUENCY INTERFERENCE STATEMENTS
This equipment generates, uses, and can radiate radio frequency energy and if not
installed and used properly, that is, in strict accordance with the manufacturer’s
instructions, may cause interference to radio communication. It has been tested
and found to comply with the limits for a Class A computing device in accordance
with the specifications in Subpart B of Part 15 of FCC rules, which are designed to
provide reasonable protection against such interference when the equipment is
operated in a commercial environment. Operation of this equipment in a
residential area is likely to cause interference, in which case the user at his own
expense will be required to take whatever measures may be necessary to correct the
interference.
Changes or modifications not expressly approved by the party responsible
for compliance could void the user’s authority to operate the equipment.
This digital apparatus does not exceed the Class A limits for radio noise emission from
digital apparatus set out in the Radio Interference Regulation of Industry Canada.
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites
applicables aux appareils numériques de la classe A prescrites dans le Règlement sur le
brouillage radioélectrique publié par Industrie Canada.
EUROPEAN UNION DECLARATION OF CONFORMITY
This equipment complies with the requirements of the European EMC Directive
89/336/EEC.
2
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
NORMAS OFICIALES MEXICANAS (NOM)
ELECTRICAL SAFETY STATEMENT
INSTRUCCIONES DE SEGURIDAD
1. Todas las instrucciones de seguridad y operación deberán ser leídas antes de
que el aparato eléctrico sea operado.
2. Las instrucciones de seguridad y operación deberán ser guardadas para
referencia futura.
3. Todas las advertencias en el aparato eléctrico y en sus instrucciones de
operación deben ser respetadas.
4. Todas las instrucciones de operación y uso deben ser seguidas.
5. El aparato eléctrico no deberá ser usado cerca del agua—por ejemplo, cerca
de la tina de baño, lavabo, sótano mojado o cerca de una alberca, etc..
6. El aparato eléctrico debe ser usado únicamente con carritos o pedestales que
sean recomendados por el fabricante.
7. El aparato eléctrico debe ser montado a la pared o al techo sólo como sea
recomendado por el fabricante.
8. Servicio—El usuario no debe intentar dar servicio al equipo eléctrico más allá
a lo descrito en las instrucciones de operación. Todo otro servicio deberá ser
referido a personal de servicio calificado.
9. El aparato eléctrico debe ser situado de tal manera que su posición no
interfiera su uso. La colocación del aparato eléctrico sobre una cama, sofá,
alfombra o superficie similar puede bloquea la ventilación, no se debe colocar
en libreros o gabinetes que impidan el flujo de aire por los orificios de
ventilación.
10. El equipo eléctrico deber ser situado fuera del alcance de fuentes de calor
como radiadores, registros de calor, estufas u otros aparatos (incluyendo
amplificadores) que producen calor.
11. El aparato eléctrico deberá ser connectado a una fuente de poder sólo del
tipo descrito en el instructivo de operación, o como se indique en el aparato.
3
NOM STATEMENT
12. Precaución debe ser tomada de tal manera que la tierra fisica y la polarización
del equipo no sea eliminada.
13. Los cables de la fuente de poder deben ser guiados de tal manera que no
sean pisados ni pellizcados por objetos colocados sobre o contra ellos,
poniendo particular atención a los contactos y receptáculos donde salen del
aparato.
14. El equipo eléctrico debe ser limpiado únicamente de acuerdo a las
recomendaciones del fabricante.
15. En caso de existir, una antena externa deberá ser localizada lejos de las lineas
de energia.
16. El cable de corriente deberá ser desconectado del cuando el equipo no sea
usado por un largo periodo de tiempo.
17. Cuidado debe ser tomado de tal manera que objectos liquidos no sean
derramados sobre la cubierta u orificios de ventilación.
18. Servicio por personal calificado deberá ser provisto cuando:
A: El cable de poder o el contacto ha sido dañado; u
B: Objectos han caído o líquido ha sido derramado dentro del aparato; o
C: El aparato ha sido expuesto a la lluvia; o
D: El aparato parece no operar normalmente o muestra un cambio en su
desempeño; o
E: El aparato ha sido tirado o su cubierta ha sido dañada.
4
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
TRADEMARKS USED IN THIS MANUAL
Cisco®is a registered trademark of Cisco Systems.
IPX™ is a trademark of Novell Incorporated.
Any other trademarks mentioned in this manual are acknowledged to be the property of the
trademark owners.
5
CONTENTS
Contents
Chapter Page
1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. PPP Operational Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4. Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1 Connecting the DSL Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2 Connecting the 10BASE-T Ethernet Port to a PC (DTE) . . . . . . . . . . . . 17
5.3 Connecting the 10BASE-T Ethernet Port to a Hub (DCE) . . . . . . . . . . . 18
5.4 Power Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6. Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.1 Power-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.2 LED Status Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.3 Test Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.3.2 Restart Procedure and Timeouts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.3.3 Loops and Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6.3.4 Using the V.52 (BER) Test-Pattern Generator . . . . . . . . . . . . . . . . . . 25
Appendix: Transmission Distance Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
1. Specifications
Clocking Modes: Internal or Receive Recovered
DTE Rates: 64, 128, 192, 256, 320, 384, 448, 512, 576, 640, 704, 768, 832, 896, 960,
1024, 1088, 1152 kbps
Line Rates (DSL Line): 144, 272, 400, 528, 784, 1040, 1168 kbps
Transmission Line: Single twisted pair
Line Coding: 2B1Q
Line Interface: Transformer coupled, 1500-VAC isolation
Diagnostics: V.52-compliant (511/511E) pattern generator and detector with error
injection mode and remote loopback control by a single front-panel switch
Indicators: LEDs: DSL Link (green active); 10BT Link (green active) valid
Ethernet connection; Status (flashing yellow) indication from the Ethernet port;
NS (red active) no signal on DSP link; ER (flashing red) CRC error during patterngeneration test; TM (active yellow) test mode enabled
Configuration: Externally accessible DIP switches or SNMP managed through DSL
Rack Card (ME0003C)
Connectors: RJ-45, 10BASE-T 802.3 Ethernet
Address Aging: Entries are deleted after 8 minutes of inactivity
Frame Latency: 1 frame
Frame Buffer: 512 frames
Ethernet Physical Connection: Pin 1 TX Data +; Pin 2 TX Data -; Pin 3 RX Data +;
Pin 4 RX Data -; Pins 4, 5, 7, 8 no connection
Power: +5 external desktop power supply, 100 to 240 VAC, 50 to 60 Hz (universal
input), 10 W
Size: 1.6"H x 4.7"W x 5"D (4.1 x 11.9 x 12.7 cm)
Weight: 0.58 lb. (0.26 kg)
7
CHAPTER 2: Introduction
2. Introduction
2.1 Description
The 2-Wire Short-Range DSL Line Driver (HDSL) 10BASE-T is a multi-rate DSL
modem that provides seamless MAC Layer connectivity between two peered
10BASE-T LANs. Enterprise users no longer need to hassle with a bridge and a
CSU/DSU or recurring leased-line costs. The HDSL Line Driver lets you a) add
additional nodes to a LAN that has reached its maximum distance limits, or
b) separate high-traffic areas of a LAN. The Line Driver connects peered LANs and
automatically forwards and receives LAN broadcasts, multicasts, and frames across
a 2-Wire DSL span. The Line Driver is 802.3 compliant and supports PPP (RFC
1661) and BCP (RFC 1638).
The HDSL Line Driver features include loopback diagnostics, inband
SNMP/HTTP remote management capabilities using Plug-and-Play, and externally
accessible configuration switches. As a symmetric DSL modem, the Line Driver
offers the same data rates in both directions over a single pair of regular telephone
lines using 2B1Q modulation. The Line Driver connects to the DSL line via an
RJ-45 jack. Power is supplied via a universal (100 to 240-VAC) power supply.
2.2 Features
• Provides MAC level (Layer 2) connection between two peered 10BASE-T
Ethernet LANs.
• Operates transparently to higher-level protocols such as TCP/IP, DECnet,
NETBEUI, and IPX™.
• PPP (Point-to-Point Protocol, RFC 1661) with Bridge Control Protocol (RFC
1638).
• Automatically discovers, loads, and deletes MAC addresses.
• Point-to-point connectivity over 2-wire HDSL up to 5 km.
• HTTP/SNMP Manageable as CP (Customer Premises) unit with a High-Speed
2-Wire Short-Range DSL Rack Card (ME0003C) CO (Central Office).
• Internal or receive recovered clocking between units.
• LED indicators for 10BASE-T Link, DSL Link, Status, No Signal, Error, and
Test Mode.
8
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
3. PPP Operational Background
PPP is a protocol used for multiplexed transport over a point-to-point link. PPP
operates on all full-duplex media. It’s a symmetric peer-to-peer protocol, which can
be broken into three main components:
1. A standard method to encapsulate datagrams over serial links.
2. A Link Control Protocol (LCP) to establish, configure, and test the data-link
connection.
3. A family of Network Control Protocols (NCPs) to establish and configure
different network layer protocols.
In order to establish communications over a point-to-point link, each end of the
PPP link must first announce its capabilities and agree on the parameters of the
link’s operation. This exchange is facilitated through LCP Configure-Request
packets.
Once the link has been established and optional facilities have been negotiated,
PPP will attempt to establish a network protocol. PPP will use Network Control
Protocol (NCP) to choose and configure one or more network layer protocols.
Once each of the network layer protocols have been configured, datagrams from
the established network layer protocol can be sent over the link. The link will
remain configured for these communications until explicit LCP or NCP packets
close the link down, or until some external event occurs.
The PPP Bridging Control Protocol (BCP), defined in RFC 1638, configures and
enables/disables the bridge protocol on both ends of the point-to-point link. BCP
uses the same packet exchange mechanism as the Link Control Protocol (LCP).
BCP is a Network Control Protocol of PPP; bridge packets may not be exchanged
until PPP has reached the network layer protocol phase.
Applications
In situations where a routed network requires connectivity to a remote Ethernet
network, the interface on a router can be configured as a PPP IP half-bridge. The
serial line to the remote bridge functions as a virtual Ethernet interface, effectively
extending the router’s serial port connection to the remote network. The bridge
device sends bridge packets (BPDUs) to the router’s serial interface. The router
will receive the layer three address information and will forward these packets
based on its IP address.
9
CHAPTER 3: PPP Operational Background
Figure 3-1 shows a typical Cisco®router with a serial interface configured as a PPP
half-bridge. The router serial interface uses a remote device that supports PPP
bridging to function as a node on the remote Ethernet network. The serial
interface on the Cisco router will have an IP address on the same Ethernet subnet
as the bridge. For example, the customer site is assigned the addresses
192.168.1.0/24 through 192.168.1.1/24. The address 192.168.1.1/24 is also the
default gateway for the remote network. The above settings remove any
routing/forwarding intelligence from the CPE. The associated Cisco configuration
will set serial interface (s0) to accommodate half-bridging for the above example.
Figure 3-1. Cisco router configured as a PPP half-bridge.
Customer site
Service provider’s network
Ethernet LAN
Internet
Router
Bridge
10
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
Some networking systems do not define network numbers in packets sent out over
a network. If a packet does not have a specific destination network number, a
router will assume that the packet is set up for the local segment and will not
forward it to any other sub-network. However, in cases where two devices need to
communicate over the wide area, bridging can be used to transport non-routable
protocols.
11
CHAPTER 4: Configuration
4. Configuration
The HDSL Line Driver has two sets of eight DIP switches. This chapter describes
switch locations and explains all settings.
Configuring the Hardware DIP Switches
The 16 external switches are grouped into two eight-switch sets. They’re externally
accessible from the underside of the HDSL Line Driver, as shown in Figure 4-1.
Figure 4-1. Underside of the HDSL Line Driver,
showing the location of the DIP switches.
The two sets of DIP switches on the underside of the HDSL Line Driver are called
S2 and S3. As Figure 4-2 shows, the orientation of all DIP switches is the same with
respect to ON and OFF positions.
Figure 4-2. Close-up of configuration switches
(all sets are identical in appearance).
ON
18234567
ON
18234567
ON
OFF
S2
S3
FRONT
REAR
12
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
DIP-S
WITCH
S2
The only setting for S2 is for clocking mode between HDSL Line Drivers. All other
switches are reserved for factory use and must remain in the default configuration.
Default settings are shown in the Table 4-1.
Table 4-1. S2 summary.
Position Function Factory Default
S2-1 Reserved Off
S2-2 Reserved Off
S2-3 Reserved Off
S2-4 Reserved Off
S2-5 Reserved Off
S2-6 Clock Mode On
S2-7 Clock Mode Off
S2-8 Reserved Off
Switch S2-1, S2-2, S2-3, S2-4, S2-5, and S2-8:
These switches are reserved for factory use and must remain in the factory-default
settings as shown in Table 4-1.
Switches S2-6 and S2-7: Clock Mode
Use Switches S2-6 and S2-7 to configure internal or receive recover (clocking
derived from the remote HDSL Line Driver across the DSL span) settings. One
Line Driver (typically the CO, or “Central Office” unit) will be set for internal
clock. The remote Line Driver (typically the CP, or Customer Premises unit) will
be set for receive recover clocking. Table 4-2 shows the clock mode settings.
}
Receive Recover
13
CHAPTER 4: Configuration
Table 4-2. Clock mode.
CO/CP Unit S2-6 S2-7 Clock Mode Description
CO On On Internal HDSL Line Driver
generates internal, crystal
controlled timing.
CP On Off Receive Recover HDSL Line Driver receives
its timing from the CO unit
over the DSL span.
DIP-S
WITCH
S3
Use the DIP switches in Switch S3 to set the DTE Rate (for LAN bandwidth
allocation) and to reset the unit to its software default settings. Table 4-3
summarizes default positions of DIP-switch S3. Detailed descriptions of each switch
follow the table.
Table 4-3. S3 summary.
Position Function Factory Default
S3-1 DTE Rate On
S3-2 DTE Rate Off
S3-3 DTE Rate Off
S3-4 DTE Rate Off
S3-5 DTE Rate On
S3-6 DTE Rate On
S3-7 Reset Software Defaults On Normal Operation
S3-8 Reserved On
}
768 kbps
14
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
Switch S3-1 through S3-6: DTE Rate
Use Switch S3-1 through S3-6 to provision bandwidth to the LAN in 64-kbps
increments up to 1.152 Mbps. Peak bandwidth utilization on the local domain on
an Ethernet LAN runs typically between 15% to 20% (1.5 Mbps to 2 Mbps) of the
maximum bit rate of 10 Mbps. Traffic between LANs typically runs even lower—
between 2% to 7% (200 kbps to 700 kbps) of the maximum bit rate depending
upon application and environmental conditions. This is the amount of traffic that
will run across the DSL span.
Set Switches S3-1 through S3-6 to allocate bandwidth based upon expected LAN-toLAN traffic rates. For example, set applications with low LAN-to-LAN bandwidth
content between 64 kbps and 576 kbps. Applications with high bandwidth LAN-toLAN content should be set between 576 kbps and 1.152 Mbps as required.
Table 4-4. DTE rate.
S3-1 S3-2 S3-3 S3-4 S3-5 S3-6 DTE Rate (kbps)
Off Off On On On On 64
On On Off On On On 128
Off On Off On On On 192
On Off Off On On On 256
Off Off Off On On On 320
On On On Off On On 384
Off On On Off On On 448
On Off On Off On On 512
Off Off On Off On On 576
On On Off Off On On 640
Off On Off Off On On 704
On Off Off Off On On 768
Off Off Off Off On On 832
On On On On Off On 896
OffOnOnOnOffOn 960
On Off On On Off On 1024
Off Off On On Off On 1088
On On Off On Off On 1152
15
CHAPTER 4: Configuration
NOTE
The actual line rate of the Line Driver is determined by the selection of
the DTE rate. To see the line rate associated with various DTE rates,
refer to the distance chart in the Appendix.
Switch S3-7: Reset Software Defaults
Use Switch S3-7 to reset the software-configured factory defaults. This feature is
applicable only using the Managed Micro Rack SNMP/HTTP Card (part number
RM261C-SNMP) to SNMP manage your units. For more information, please refer
to the Managed Micro Rack SNMP/HTTP Card Users’ Manual.
Table 4-5. Reset software defaults.
S3-7 Setting
On Normal Operation
Off Reset
Switch S3-8: Reserved
Switch S3-8 is reserved for factory use and must remain in the On position.
16
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
5. Installation
When the HDSL Line Driver has been properly configured, it may be connected to
the DSL twisted-pair interface, the 10BASE-T Ethernet interface, and the power
source. Figure 5-1 shows the locations of these interface ports.
Figure 5-1. Rear panel.
5.1 Connecting the DSL Interface
The HDSL Line Driver supports communication between 10BASE-T hubs or
workstations at distances to 5 miles (8 km) over 24-AWG (0.5-mm) twisted-pair
wire. Two things are essential:
1. These units operate as a pair. Both units at the end of the twisted-pair DSL
span must be set for the same DTE rate.
2. To function properly, the HDSL Line Driver needs one twisted pair of
metallic wire. This twisted pair must be unconditioned, dry, metallic wire,
between 19 (0.9 mm) and 26 AWG (0.4 mm); the higher number gauges will
limit distance. Standard dial-up telephone circuits, leased circuits that run
through signal equalization equipment, or standard, flat modular telephone
type cable will not work!
The RJ-45 connector on the HDSL Line Driver’s twisted-pair interface is polarity
insensitive and is wired for a two-wire interface. The signal/pin relationships are
shown in Figure 5-2.
10BASE-T
interface
17
CHAPTER 5: Installation
Figure 5-2. Twisted-pair line interface.
NOTE
The HDSL Line Driver has been optimized for performance at high bit
rates (DTE rates greater than 512 kbps). To ensure accurate
performance at these bit rates, please use twisted-pair line interface
cable that is at least 330 ft. (100 m) long.
5.2 Connecting the 10BASE-T Ethernet Port to a PC (DTE)
The 10BASE-T interface is configured as DTE (Data Terminal Equipment). If the
HDSL Line Driver connects to another DTE device such as a 10BASE-T network
interface card, construct a 10BASE-T crossover cable and connect the wires as
shown in Figure 5-3.
10BASE-T Port 10BASE-T DTE
RJ-45 Pin No. RJ-45 Pin No.
1 (TD+) 1 (TD+)
2 (TD-) 2 (TD-)
3 (RD+) 3 (RD+)
6 (RD-) 6 (RD-)
Figure 5-3. Crossover cable connections.
18
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
5.3 Connecting the 10BASE-T Ethernet Port to Hub (DCE)
The 10BASE-T interface is configured as DTE (Data Terminal Equipment) just like
a 10BASE-T network interface card in a PC. Therefore, it “expects” to connect to a
10BASE-T hub using a straight-through RJ-45 cable. Use Figure 5-4 to construct a
cable to connect the 10BASE-T interface to a 10BASE-T hub.
10BASE-T Port 10BASE-T Hub
RJ-45 Pin No. RJ-45 Pin No.
1 (TD+) 1 (RD+)
2 (TD-) 2 (RD-)
3 (RD+) 3 (TD+)
6 (RD-) 6 (TD-)
Figure 5-4. Straight-through cable connections.
Figure 5-5. 10BASE-T Ethernet RJ-45 connector pinout.
5.4 Power Connection
The HDSL Line Driver uses a 5-VDC, 2-A universal input 100- to 240-VAC power
supply (center pin is +5V). The power supply has a male IEC-320 power entry
connector. Connect the power supply to the HDSL Line Driver via a barrel jack on
the rear panel.
The Line Driver powers up as soon as it is plugged into an AC outlet; there is no
power switch.
TD+ (data output from 1089)
TD- (data output from 1089)
RD+ (data input to 1089)
(no connection)
(no connection)
RD- (data input to 1089)
(no connection)
(no connection)
(data output from Line Driver)
(data output from Line Driver)
(data input to Line Driver)
(data input to Line Driver)
19
CHAPTER 5: Installation
WARNING
There are no user-serviceable parts in the power supply. Contact Black
Box Technical Support at 724-746-5500 for more information.
20
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
6. Operation
When the HDSL Line Driver has been properly configured and installed, it should
operate transparently. This chapter describes power-up, LED status indicators, and
the built-in loopback test modes.
6.1 Power-Up
Before applying power to the HDSL Line Driver, please read Section 5.4 and make
sure that the unit will be connected to the appropriate power source.
6.2 LED Status Indicators
The HDSL Line Driver features six front-panel LEDs that monitor connections on
the DSL and 10BASE-T links, signaling, error, and test modes. Figure 6-1 shows the
location of each LED. Descriptions of each LED follow Figure 6-1.
Figure 6-1. Front panel.
• DSL Link: (active green) Solid green (On) indicates that the end-to-end DSL
framer link is up, signifying that the link across the DSL span is active. The
DSL Link LED is Off when the link is down.
• Status: Blinks yellow from one to eleven times to indicate system status. Each
pulse pattern is separated by a 2-second “off” period. Greater pulse patterns
have higher priority (buffer saturation has greater priority than an empty MAC
table). Valid system statuses are:
1 pulse = system status is okay
2 pulses = no MAC entries in the MAC Address Table
21
CHAPTER 6: Operation
3 pulses = Clear to Send (CTS) or Carrier Detect (DCD) from base
unit are not asserted
4 pulses = Line Driver buffer is saturated
5 pulses = WAN receive frame(s) too large
6 pulses = WAN receive frame(s) not octet aligned
7 pulses = WAN receive frame(s) aborted
8 pulses = Detected WAN receive frame(s) with CRC
9 pulses = Detected LAN receive frame(s) too large
10 pulses = Detected LAN receive frame(s) not octet aligned
11 pulses = Detected LAN receive frame(s) with bad CRC
• 10BT Link: (active green) Solid green indicates that the 10BASE-T Ethernet
interface has detected a valid SQE heartbeat, signifying a valid 10BASE-T
connection.
• NS: (active red) Solid red indicates that the Digital Signal Processors (DSPs)
are not linked.
• ER: (active red) Flashing red indicates CRC Errors on the DSL (Framer) side if
the DSL Link is active or if bit errors are received during loop/BER test.
ER flashes once to indicate a CRC error (during normal operation) or bit
errors (during remote loopback 511/511E tests).
• TM: (active yellow) Solid yellow indicates an active test mode. The unit may be
placed in test mode by the local user or by the remote user.
22
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
Table 6-1. LED descriptions.
LOCAL REMOTE
10BT DSL Status NS ER TM 10BT DSL Status NS ER TM
Power On G* Off F On Off Off G* Off F On Off Off
DSL Link G* G F Off Off Off G* Off F Off Off Off
Link Brk G* Off F Off Off Off G* Off F Off Off Off
Brk + 10s G* Off F On Off Off G* Off F On Off Off
RDL G* G F Off Off On G* Off F Off Off On
RDL + 511 G* Off F Off Off On G* Off F Off Off On
With DTE Connected With DTE Connected
Mark G* G F Off Off Off G* G F Off Off Off
Space G* G F Off Off Off G* G F Off Off Off
Data G* G F Off Off Off G* G F Off Off Off
Link Brk = DSL Link Broken
Brk + 10s = 10 seconds following link break
G = Green
F = Flashing
G* = Green if a valid 10BASE-T connection is detected
6.3 Test Modes
The HDSL Line Driver offers proprietary remote loopback test modes, plus a builtin V.52 BER test-pattern generator to evaluate the communication status between
units. Activate this test mode by toggling the test mode switch on the front panel of
the unit.
6.3.1 O
VERVIEW
Figure 6-2 shows the major elements used in the loopback and 511 pattern tests
available in the HDSL Line Driver. Each block has several functions. Following
Figure 6-2 are descriptions of the elements during test modes.
23
CHAPTER 6: Operation
Figure 6-2. Block diagram of the major elements used in the tests.
Framer
The framer determines the status of the line. In normal operation, the framer
transmits and expects to receive framed packets from the far end. If the framer
receives framed packets from the far end, the DSL Link LED will turn on. If
framed packets are not received, the DSL Link LED will turn off. The restart
procedure uses this information to determine if a valid connection is made (cable
disconnect, poor cable quality, etc.). In normal data mode, if the box receives four
seconds of unframed packets, it will restart the box and begin trying to re-establish
a connection with the the remote Line Driver. The distinction between framed
packets and unframed packets becomes important when we discuss the pattern
generator.
Pattern Gen./Det.
This part of the processor generates and detects the 511/511E patterns. When
transmitting 511 patterns, the information is unframed (because it originates after
the framer) and is intended to be evaluated only by another processor. If the units
are transmitting data and the pattern generator is enabled on one end of the link,
the far end will begin receiving unframed packets and assume that the line has
gone down. During test modes, the pattern generator is forced to time out before
it can cause the DSL link to go down.
Loop Control
This part of the processor is used to control remote loopback test mode. In a
remote loop, the 511/511/E data is looped back to the line and to the remote unit
over the DSL span.
Framer
Processor Processor
Framer
Pattern
Gen./Det.
Pattern
Gen./Det.
Loop
Control
Loop
Control
DSL
Span
24
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
6.3.2 R
ESTART
P
ROCEDURE ANDTIMEOUTS
The restart procedure is in place to allow the units to re-establish a connection
after the framer begins seeing unframed packets. Table 6-2 shows the amount of
time the framer must see consecutive unframed packets before the unit will restart
and try to establish a new line connection. The reason that there are different
restart times will become apparent after reading the rest of the document. The
511/511E timeout shown refers to the amount of time the 511/511E pattern will
be valid. At the end of this time, the pattern will automatically turn itself off and
the normal data path will be re-established. The ER LED will flash, indicating that
the test has timed out. The ER LED will stop flashing once the 511/511E switch is
placed into the normal position.
Table 6-2. Test mode timing.
Item Elapsed Time (seconds)
Startup 50
Data Mode 4
511/511E Generator Enabled 60 (The generator will stop after 45
seconds.)
Remote End of an RDL 60
511/511E Timeout 45 (The pattern generator will
automatically turn off after 45 seconds.
The ER LED will flash until you turn off
the 511/511E switch.)
Symbol Indicators
This symbol designates the origination or the termination of a data path. The
direction of the arrow connected distinguishes the two data paths.
This symbol designates an invalid data path. If there is data present, it should
be ignored.
X
25
CHAPTER 6: Operation
6.3.3 L
OOPS AND
P
ATTERNS
The following section describes the remote loopback/BER test modes.
Remote Digital
When remote loop/511 or remote loop/511E is enabled via the front-panel switch,
the remote unit’s restart timer is set to one minute. It does this because when the
511/511E generator is initiated on the local unit, the remote framer begins seeing
unframed packets. The remote unit cannot distinguish the 511/511E pattern from
the line being disconnected, so the restart timer has been lengthened to allow the
pattern generator to function. Once the 511/511E test is started, the local unit
changes its restart timer to one minute. The pattern originates within the
processor and is sent to the remote unit. It is then looped back to the local unit
where it is evaluated for errors. After 45 seconds, the pattern generator will
timeout and stop sending the pattern. The ER LED will begin blinking until you
turn off the 511/511E switch.
Figure 6-3. Block diagram showing two Line Drivers
communicating over the DSL span.
6.3.4 U
SING THE
V.52 (BER) T
EST-PATTERNGENERATOR
To use the V.52 BER tests in conjunction with the remote digital loopback tests,
follow these instructions:
1. Locate the remote loop/511 and remote loop/511E toggle switch on the
front panel of the Line Driver and move it DOWN. This activates the remote
loop with V.52 BER and transmits a 511 test pattern into the loop. If any
errors are present, the local unit’s red ER LED will blink sporadically.
Framer
X
X
X
X
Processor
Processor
Framer
Pattern
Gen./Det.
Pattern
Gen./Det.
Loop
Control
Loop
Control
DSL
Span
26
2-WIRE SHORT-RANGE DSL LINE DRIVER (HDSL) WITH 10BASE-T
2. If the test indicates no errors are present, move the test switch V.52 toggle
switch up, activating the 511E test with intentional errors present. If the test is
working properly, the local unit’s red ER LED will blink. A successful 511E
test will confirm that the link is in place, and that the Line Driver’s built-in
511 generator and detector are working properly.
27
APPENDIX: Transmission Distance Charts
Appendix. Transmission Distance
Charts
Table A-1. Transmission distance HDSL Line Driver, no crosstalk.
Line Rate DTE Rates 26 AWG (0.4 mm) 24 AWG (0.5 mm)
(kbps) (kbps) ft. mi. km ft. mi. km
144 64, 128 20,700 3.9 6.3 24,500 4.6 7.5
272 192, 256 17,400 3.3 5.3 24,200 4.6 7.4
400 320, 384 15,100 2.9 4.6 22,600 4.3 6.9
528 448, 512 14,900 2.8 4.5 21,000 4 6.4
784 576, 640, 13,500 2.6 4.1 18,000 3.4 5.5
704, 768
1040 832, 896, 11,900 2.2 3.6 15,500 2.9 4.7
960, 1024
1168 1088, 1152 11,000 2.1 3.3 15,200 2.9 4.6
Table A-2. Transmission distance HDSL Line Driver, crosstalk (49 adjacent
CAP pairs).
Line Rate DTE Rates 26 AWG (0.4 mm) 24 AWG (0.5 mm)
(kbps) (kbps) ft. mi. km ft. mi. km
144 64, 128 18,600 3.5 5.7 22,100 4.2 6.7
272 192, 256 15,700 3 4.8 21,800 4.1 6.6
400 320, 384 12,800 2.4 3.9 19,200 3.6 5.9
528 448, 512 13,000 2.5 4 18,300 3.5 5.6
784 576, 640, 12,200 2.3 3.7 16,200 3.1 4.9
704, 768
1040 832, 896, 10,500 2 3.2 13,600 2.6 4.1
960, 1024
1168 1088, 1152 9400 1.8 2.9 12,900 2.4 3.9
1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax 724-746-0746
© Copyright 2001. Black Box Corporation. All rights reserved.
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