Black Box T1 CSU/DSU User manual

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Mailing address: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
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CUSTOMER
SUPPORT
INFORMATION
DECEMBER 2001
MT100A-35-R2
MT100A-449-R2
MT100A-530-R2
T1 CSU/DSU (V.35)
T1 CSU/DSU (449)
T1 CSU/DSU (530)

FCC STATEMENT
1
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.

T1 CSU/DSU (V.35, 449, or 530)
2
INSTRUCCIONES DE SEGURIDAD (Normas Oficiales Mexicanas Electrical Safety Statement)
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.
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.

TRADEMARKS
3
TRADEMARKS USED IN THIS MANUAL
Accunet and AT&T are registered trademarks of AT&T.
UL is a registered trademark of Underwriters Laboratories Incorporated.
Any other trademarks mentioned in this manual are acknowledged to be the property of the trademark owners.
Registration Numbers
FCC Registration Number (unit) .................................GBRUSA-18888-DE-N
UL®listing (power supply) ...........................................UL3458
DS&G Registration Number .........................................US Safety: E3067
Canadian Use Registration Number ............................1596 4190 ACS03-7784
CSA Registration Number (unit) .................................CSA LR3067
CSA Registration Number (power supply)..................CSA LR60602

T1 CSU/DSU (V.35, 449, or 530)
4
Contents
Chapter Page
1. Specifications ..........................................................................................................................................................5
2. Introduction............................................................................................................................................................8
2.1 Overview........................................................................................................................................................8
2.2 Bantam Jacks ................................................................................................................................................8
2.3 Loopback Switches ......................................................................................................................................8
2.3.1 Remote CSU/Aggregate Loopback ..............................................................................................9
2.3.2 Remote Channel Loopback ............................................................................................................9
2.3.3 Local Channel Loopback Diagnostic ............................................................................................9
2.3.4 Local Aggregate Loopback ..........................................................................................................10
2.4 Network LEDs ............................................................................................................................................10
2.5 Channel LEDs ............................................................................................................................................10
2.6 Rear-Panel Controls and Interface Connectors ......................................................................................11
2.7 Channel Interface Connections ................................................................................................................11
2.7.1 Power Connection ........................................................................................................................12
2.7.2 Network Connection ....................................................................................................................12
3. Installation ............................................................................................................................................................14
3.1 Introduction................................................................................................................................................14
3.2 Site Preparation ..........................................................................................................................................14
3.3 Installation Procedure................................................................................................................................14
3.4 Equipment Cabling ....................................................................................................................................14
3.4.1 Network Cabling ............................................................................................................................14
3.4.2 DTE Channel Cabling ..................................................................................................................15
3.4.3 Power Cabling and Initial Power Up............................................................................................15
4. Operation..............................................................................................................................................................16
4.1 Modify Configuration ................................................................................................................................16
4.2 Configuration Tables..................................................................................................................................22
Appendix: FCC Documentation Requirements ......................................................................................................25

CHAPTER 1: Specifications
5
1. Specifications
Configuration
- DIP-switch selectable, readily accessible from the rear panel
Aggregate
- Recommended Cable Requirement: STP
- Line Rate: 1.544 Mbps ±50 bps
- Line Format: AMI or B8ZS
- Framing Format: D4 or ESF(Fe)
- Pulse Characteristics: AT&T®62411 compliance
- Output Amplitude: 2.4 to 3.3 V peak to base
- Receiver Sensitivity: 0 to -26 dB
- Line Build-Out (CSU): 0 dB, -7.5 dB, -15 dB
- Line Distance (DSX-1 Mode): 0 to 655 feet (0 to 200 m)
- Line Distance (CSU Mode): 0 to 6000 feet (0 to 1828.8 m) with 24 AWG
- Interface: RJ-45
- Density Monitoring: 1 of 16, 1 of 48, 1 of 64, or none
Internal CSU
- Meets FCC Part 68 requirements
- Meets AT&T Pub 62411
- Local and Remote Loopback Diagnostics
- Type 1 Keep-Alive Signal
Clocking Modes
- Internally provided
- External from network (loop)
- External from channel

T1 CSU/DSU (V.35, 449, or 530)
6
DTE Channels
MT100A-35-R2: CCITT V.35 interface; 34-pin M block (female) connector
MT100A-449-R2: EIA RS-449 interface; DB37(female) connector
MT100A-530-R2: EIA RS-530 interface; DB25 (female) connector
- Density: Alternate DS0 (Fractional T1), Bit 7 stuffing, or None
- Selectable DTE Channel Rates N x 56 kbps (56, 112, 168, 224, 336, 448, 672, or 1344)
- Selectable DTE Channel Rates N x 64 kbps (64, 128, 192, 256, 384, 512, 768, or 1536)
Compatibility
- AT&T Pub 62411
- AT&T Pub 54019A
- Carrier T1 Service Offerings
- Carrier Fractional T1 Service Offerings
Approvals
- FCC Parts 15 and 68
- UL
- CSA
Diagnostics
- Local Aggregate Loopback
- Remote CSU Loopback
- Local and Remote Channel Loopbacks
- Tx/Rx Monitor Jacks and Network In and Network Out Jacks
- Test LED lit when active

CHAPTER 1: Specifications
7
Front-Panel Network Indicators
- Loss Of Signal (LOS)
- Bipolar Violations (BPV)
- Synchronization
- Red Alarm
- Yellow Alarm
- Test
Front-Panel DTE Channel Indicators
- Transmit Data (TD)
- Receive Data (RD)
- Request To Send (RTS)
- Receive Line Signal Detect (RLSD)
Mean Time Between Failure (Estimated)
40,000 hours
Environmental
- Temperature: 32 to 122°F (0 to 50°C)
- Storage Temperature: -4 to +176°F (-20 to +80°C)
- Relative Humidity: Up to 95% noncondensing
- Maximum Altitude: 15,000 ft. (4572 m)
Standalone Unit
- Size: 1.5"H x 7.25"W x 10.5"D (3.8 x 18.4 x 26.7 cm)
- Weight: 2 lb. (0.9 kg)
- Power: External wallmount power supply

T1 CSU/DSU (V.35, 449, or 530)
8
2. Introduction
2.1 Overview
The T1 CSU/DSU is a high-speed T1 format processor with one of three interfaces for the DTE channel:
CCITT V.35, RS-449, or RS-530. It is capable of processing data at speeds from 56 kbps to 1.536 Mbps,
depending upon the format and density requirements of the application. It provides all the framing and density
requirements for data transmission across predefined network facilities, such as Accunet®.
The T1 CSU/DSU, because of its unique design, is able to accept timing information from any clock. Timing
information may be derived from the receive data, an external DTE, or from the internal crystal oscillator. The
T1 CSU/DSU has a series of selectable diagnostics that allow you to quickly and accurately troubleshoot the T1
CSU/DSU and the associated network.
The T1 CSU/DSU has a built-in CSU which complies with AT&T Publication 62411. This allows you to attach
the T1 CSU/DSU directly to the T1 circuit. This CSU can be enabled or disabled with a simple switch setting so
that the unit can act as a DSU or as a DSU/CSU. It can also be used as a high-speed line driver to extend high-
speed data circuits up to 6000 feet (1828.8 m) over shielded twisted-pair (STP) cable.
The T1 CSU/DSU contains all the controls and indicators necessary to configure, monitor, diagnose, and
operate the system. The front panel contains four bantam jack receptacles for network data monitoring and test
signal injection, loopback selection switches for aggregate and channel loopbacks, and a series of LEDs that
reflect the status of both the network and the DTE channel.
2.2 Bantam Jacks
The bantam jacks, located on the T1 CSU/DSU’s front panel, provide easy access to both monitor
the T1 service without interrupting the transmission of information or to inject a test signal to exercise the T1
circuit.
To monitor the T1 service, connect a test set to the T1 CSU/DSU via the Transmit Monitor (NET TX MON)
bantam jack and the Receive Monitor (NET RX MON) bantam jack. This allows the user to monitor the T1
service without interrupting the information flow.
To inject and receive a test signal across the T1 transmission facility, connect the test set into the IN (NET TX
IN) and OUT (NET RX OUT) bantam jacks. Then, place the T1 CSU/DSU in Remote Channel Loopback. In
this configuration, the operator can inject a known signal and receive it back via the network for testing
purposes. This is an interruptive test. Data integrity can not be guaranteed during this test.
2.3 Loopback Switches
There are two loopback switches on the T1 CSU/DSU’s front panel. Both switches allow the user to test
individual sections of the data transmission path. This ability to test these individual paths allows you to isolate,
diagnose, and then perform corrective action to resolve data transmission problems in the network.

CHAPTER 2: Introduction
9
2.3.1 REMOTE CSU/AGGREGATE LOOPBACK
The Remote CSU/Aggregate Loopback (see Figure 2-1) test lets you verify the logic from the local interface
through the remote aggregate and back to the local channel interface. To select this test, position the
Aggregate Loopback switch in the Remote position. When complete, return this switch to the center position.
Figure 2-1. Remote CSU/Aggregate Loopback.
2.3.2 REMOTE CHANNEL LOOPBACK
To verify the remote unit’s channel logic from the local unit (Figure 2-2), select the remote position of the
Aggregate Loopback switch. When complete, reposition this switch to the center position.
Figure 2-2. Remote Channel Loopback.
2.3.3 LOCAL CHANNEL LOOPBACK DIAGNOSTIC
Local Channel Loopback Diagnostic (Figure 2-3) enables you to verify the channel interface. To run this test,
position the Channel Loopback Switch in the Local position. When complete, reposition the switch to the
center position.
Figure 2-3. Local Channel Loopback.

T1 CSU/DSU (V.35, 449, or 530)
10
2.3.4 LOCAL AGGREGATE LOOPBACK
The Local Aggregate Loopback diagnostic (Figure 2-4) lets you verify the T1 CSU/DSU logic from the channel
interface, through the aggregate, and return to the channel interface. To select this test, position the Aggregate
Loopback switch in the Local position. When complete, reposition the switch to the center position.
Figure 2-4. Local Aggregate Loopback.
2.4 Network LEDs
Six LEDs indicate network function of the unit: Loss Of Signal (LOS), Bipolar Violations (BPV), Red and
Yellow alarms, Sync, and Test.
LOS LED — when lit, indicates the lack of sufficient signal pulses (marks) at the network receiver. The LED
lights when more than 175 consecutive zeros are received and is extinguished when the next mark is
detected.
Bipolar Violations LED — when lit, indicates that a pulse was received that is of the same polarity as
the preceding pulse (excluding B8ZS codewords), thus violating the Alternative Mark Inversion Rule.
Red Alarm LED — lit when the receiver has lost frame synchronization for 2 to 2.5 seconds.
The LED is extinguished when Frame Sync has been acquired for at least eight consecutive seconds.
Yellow Alarm LED — lit while a Yellow Alarm indication is being received from the remote unit.
The remote unit will transmit a Yellow Alarm indication while in the Red Alarm state. While operating in
D4 framing, the Yellow Alarm condition is transmitted by forcing bit 2 of every DS0 to a zero state. In ESF
framing mode, the Yellow Alarm condition is a pattern embedded in the framing overhead.
Sync LED — lit when the local unit is in Sync with the remote unit. It is extinguished when synchronization
is lost. Frame sync criteria is the receipt of 10 consecutive F bits. Sync loss criteria is receipt of 2 of 4
consecutive frame word errors.
Test LED — lit whenever the unit is in a selected diagnostic mode or test, or while the unit is sending
diagnostic patterns.
2.5 Channel LEDs
The four LEDs below the Channel heading represent the status of the channel side of the unit. The Channel
TD (green) LED lights when the channel is transmitting a space. The Channel RD (green) LED lights when
the channel is receiving a space. The Request to Send (RTS) LED lights when the Request to Send function is
active. The Channel RLSD (green) LED lights when the channel’s Receive Line Signal Detect function is active.

CHAPTER 2: Introduction
11
2.6 Rear-Panel Controls and Interface Connectors
The rear panel (Figure 2-5) provides access to the physical interfaces necessary to connect the unit to a
network. Depending on the model, there is one of the following female connectors on the rear panel for the
DTE interface: 34-pin M block (V.35), DB37 (RS-449), or DB25 (RS-530). There is also a five-pin DIN power
connector for applying logic power (-5 and ±12 VDC) to the unit. There are two DIP switches (Switch 1 and
Switch 3), along with the LBO switch (Switch 2).
NOTE
When operating as a channel service unit (CSU), the setting of the Line Build-Out
function is dictated by the carrier and must be set as the carrier specifies. Otherwise,
the LBO Switch must be set to the 0 dB position.
2.7 Channel Interface Connections
T1 CSU/DSU is configured for DTE connection with one of these three interfaces: V.35, RS-449, or RS-530
(female connectors). Below are the pinouts (male connectors) for these interfaces.
V.35 Pinout (34-pin male connector)
Pin Function Pin Function
A . . . . . . . . . . . . . . . . . . . . . . . .Ground T . . . . . . . . . . . . . . . . . . . . . . .RD(B)
D . . . . . . . . . . . . . . . . . . . . . . . . .CTS U . . . . . . . . . . . . . . . . . . . . . . . .TT(A)
E . . . . . . . . . . . . . . . . . . . . . . . . .DSR V . . . . . . . . . . . . . . . . . . . . . . .RT(A)
F . . . . . . . . . . . . . . . . . . . . . . . . .DCD W . . . . . . . . . . . . . . . . . . . . . . .TT(B)
P . . . . . . . . . . . . . . . . . . . . . . . . .SD(A) X . . . . . . . . . . . . . . . . . . . . . . .RT(B)
R . . . . . . . . . . . . . . . . . . . . . . . .RD(A) Y . . . . . . . . . . . . . . . . . . . . . . . .ST(A)
S . . . . . . . . . . . . . . . . . . . . . . . . .SD(B) AA . . . . . . . . . . . . . . . . . . . . . . .ST(B)
RS-449 Pinout (DB37 male connector)
1 ..........................................Shield
2 ..............................Signal Rate Indicator 20 . . . . . . . . . . . . . . . .Receive Common
3 ..............................................— 21 . . . . . . . . . . . . . . . . . . . . . . .—
4 ....................................Send Data (A) 22 . . . . . . . . . . . . . . . . . .Send Data (B)
5 ..................................Send Timing (A) 23 . . . . . . . . . . . . . . . . .Send Timing (B)
6 ..................................Receive Data (A) 24 . . . . . . . . . . . . . . . . .Receive Data (B)
7 ..............................Request To Send (A) 25 . . . . . . . . . . . . . . .Request to Send (B)
8 ................................Receive Timing (A) 26 . . . . . . . . . . . . . . . .Receive Timing (B)
9..................................Clear To Send (A) 27 . . . . . . . . . . . . . . . . .Clear to Send (B)
10 ..................................Local Loopback 28 . . . . . . . . . . . . . . . .Terminal in Service
11 ..................................Data Mode (A) 29 . . . . . . . . . . . . . . . . . . .Data Mode
12 ..............................Terminal Ready (A) 30 . . . . . . . . . . . . . . . .Terminal Ready (B)
13 ..............................Receiver Ready (A) 31 . . . . . . . . . . . . . . . .Receiver Ready (B)
14 ................................Remote Loopback 32 . . . . . . . . . . . . . . . . . .Select Standby
15 ....................................Incoming Call 33 . . . . . . . . . . . . . . . . . .Signal Quality
16 ................................Select Frequency 34 . . . . . . . . . . . . . . . . . . .New Signal
17 ..............................Terminal Timing (A) 35 . . . . . . . . . . . . . . . .Terminal Timing (B)
18 ......................................Test Mode 36 . . . . . . . . . . . . . . . . .Standby/Indicator
19....................................Signal Ground 37 . . . . . . . . . . . . . . . . . .Send Common
RS-530 Pinout (DB25 male connector)
1 . . . . . . . . . . . . . . . . . . . . . . . .Shield (A) 14 ......................................Transmitted Data (B)
2 . . . . . . . . . . . . . . . . . . .Transmitted Data (A) 15 ..........................Transmitter Signal Element DCE (A)
3 . . . . . . . . . . . . . . . . . . . .Received Data (A) 16 ........................................Received Data (B)
4 . . . . . . . . . . . . . . . . . . . .Request to Send (A) 17 ......................Receiver Signal Element Timing DCE (A)
5 . . . . . . . . . . . . . . . . . . . . .Clear to Send (A) 18 ..........................................Local Loopback
6 . . . . . . . . . . . . . . . . . . . . . .DCE Ready (A) 19 ..........................................Request to Send
7 . . . . . . . . . . . . . . . . . . . . . .Signal Ground 20 ..........................................DTE Ready (A)
8 . . . . . . . . . . . . . .Received Line Signal Detector (A) 21 ........................................Remote Loopback
9 . . . . . . . . . . .Receiver Signal Element Timing–DCE (B) 22 ..........................................DCE Ready (B)
10 . . . . . . . . . . . . . .Received Line Signal Detector (B) 22 ..........................................DCE Ready (B)
11 . . . . . . . . . .Transmitter Signal Element Timing–DTE (B) 23 ..........................................DTE Ready (B)
12 . . . . . . . . .Transmitter Signal Element Timing–DCE (B) 24 ....................Transmitter Signal Element Timing DTE (A)
13 . . . . . . . . . . . . . . . . . . . .Clear to Send (B) 25 ..............................................Test Mode

T1 CSU/DSU (V.35, 449, or 530)
12
2.7.1 POWER CONNECTION
The power connector (female) is on the rear panel. The male connector of the DC power supply plugs into this
female connector. Figure 2-6 shows the pinout of the 5-pin DIN connector.
2.7.2 NETWORK CONNECTION
The network connector is an RJ-48C modular connector with an RJ-48C-to-DB15 pigtail cable (not supplied).
Refer to Figure 2-7.
Figure 2-5. Rear-Panel Connections.
VM Series Regulated Table Top Power Supply
Pin 1 = Common
Pin 2 = N/C
Pin 3 = +5V
Pin 4 = -12V
Pin 5 = +12V
Figure 2-6. Power Connector Pinout.
1
5
3
2
4

CHAPTER 2: Introduction
13
Figure 2-7. Network Connector: DB15-to-RJ-48 Pigtail Cable.

T1 CSU/DSU (V.35, 449, or 530)
14
3. Installation
3.1 Introduction
This chapter has the information necessary to plan, perform, and verify the mechanical and electrical
installation of the T1 CSU/DSU. Before installing the T1 CSU/DSU, read and completely understand the
information presented here.
3.2 Site Preparation
The T1 CSU/DSU should be installed within 7 feet (2.1 m) of a grounded AC outlet furnishing 115/230 VAC.
The location should be clean, well lit, and conform to the standards for computer equipment installations.
Allow a 36-inch (91.4-cm) clearance for both the front and back of the unit for access during operation and
maintenance. When connecting the interface cables, allow 4 feet (1.2 m) of slack in the cables so that you can
move the unit to perform service without disconnecting the cables.
3.3 Installation Procedure
Before installing the T1 CSU/DSU, carefully read and understand the entire installation procedure.
Although we take great care to make sure that the T1 CSU/DSU is properly packaged so that it will not
be damaged during transit, it is your responsibility to verify that the unit arrives undamaged. Before unpacking
the T1 CSU/DSU, read the following:
1. Carefully remove all packing material from the T1 CSU/DSU.
2. Inspect the equipment for damage that may have occurred during shipment. If any damage is noted,
contact the shipping agent and the manufacturer.
NOTE
The T1 CSU/DSU shipping carton is designed to ensure that the device arrives
undamaged. If it ever becomes necessary to move the T1 CSU/DSU to another
location, save the shipping carton for such use.
3.4 Equipment Cabling
3.4.1 NETWORK CABLING
The Network connector is an RJ-48C modular type connector with an optional RJ-48C-to-DB15 pigtail cable
(not supplied). Depending upon the configuration of the network, either connect the network line cable
directly into the unit or first connect the RJ-48C-to-DB15 pigtail cable into the unit and then connect the
network line cable to the DB15 end of the pigtail cable.

CHAPTER 3: Installation
15
3.4.2 DTE CHANNEL CABLING
The T1 CSU/DSU is configured at the factory to be connected via an industry-standard channel interface using
either a V.35, RS-449, or RS-530 cable. When the DTE interface cable is in position and seated, secure it with
the two jack screws. For information about DTE interface pinouts, see Section 2.7.
3.4.3 POWER CABLING AND INITIAL POWER UP
NOTE
Before connecting the power cable to the T1 CSU/DSU, make sure that the unit is
properly configured and all interface cables are connected and seated.
Power to the T1 CSU/DSU is supplied by a separate DC power supply. Insert the power supply male DIN
connector into the female DIN connector at the rear of the unit. Insert the power cable male connector into a
grounded AC power receptacle. At this time power is applied to the T1 CSU/DSU.

T1 CSU/DSU (V.35, 449, or 530)
16
4. Operation
The T1 CSU/DSU is controlled by a series of simple switch settings that the operator can select by accessing
Switches one, two, and three at the rear of the unit.
4.1 Modify Configuration
To configure a new T1 CSU/DSU Series or modify the configuration of an existing T1 CSU/DSU Series, first
determine the correct information by reviewing the following worksheet. This worksheet should be copied and
annotated so that when completed it can be saved for future reference.
Before completing the worksheet, you should have a complete understanding of the application being served
by the T1 CSU/DSU format processor.

CHAPTER 4: Operation
17
Configuration Worksheet
Customer Name: __________________________________________________________
Date: __________________________________________________________________
Customer Location: ________________________________________________________
Configuration: ____________________________________________________________
Switch One Settings
1. Data Rate Selection (see Table 4-2) ............................................S1-1
S1-2
S1-3
2. DTE Channel Multiples N x 56 kbps: ................S1-4: On
N x 64 kbps: ................S1-4: Off
Selectable N x 56 Rates: 8, 16, 24, 32, 40, 48, 56, 64, 112, 168, 192, 224, 280, 320, 336, 448, 560,
672, 840, 960, 1120, and 1344 kbps.
NOTE
For specific speed selection information, refer to Table 4-2.
Selectable N x 64 Rates: 8, 16, 24, 32, 40, 48, 64, 128, 192, 256, 320, 384, 512, 640, 768, 960, 1280,
and 1536 kbps.
NOTE
For specific speed selection information, refer to Table 4-2.
DIP Switches: Off = Down Position; On = Up Position

T1 CSU/DSU (V.35, 449, or 530)
18
3. Channel Send Timing:
A. Loop 1 (Terminal Timing) ..................................S1-5: On
B. Loop 2 (Send Timing) ........................................S1-5: Off
4. Channel Timing:
A. Normal ..................................................................S1-6: On
B. Inverted ................................................................S1-6: Off
5. Channel Data:
A. Normal ..................................................................S1-7: On
B. Inverted ................................................................S1-7: Off
6. Request To Send Control:
A. Always On..............................................................S1-8: On
B. Controlled ............................................................S1-8: Off
7. Aggregate Timing Selection:
A. Internal (Master) Crystal Timing ..............................S1-9: On
S1-10: On
B. Loop (Slave) Timing ..................................................S1-9: Off
S1-10: On
C. External Channel Timing (see the Note below) ......S1-9: On
S1-10: Off
D. Internal (Master) Crystal Timing ..............................S1-9: Off
S1-10: Off
NOTE
If the External Channel Timing selection is made, then the associated Channel Send
Timing must be set to Loop 1 Timing. When operating in this mode, the DCE provides
the network timing.
DIP Switches: Off = Down Position; On = Up Position

CHAPTER 4: Operation
19
Switch Two Settings
1. LBO Setting. (Active only in the CSU mode of operation. When operating in the DSX-1 mode, the LBO
switch must be in the 0 dB position.) Position the LBO switch as directed by the carrier:
A. -1 5 dB
B. -7.5 dB
C. 0 dB
Switch Three Settings
1. Network Framing:
A. D4 ..........................................................................S3-1: On
B. ESF (Fe) ................................................................S3-1: Off
2. Network Line Code:
A. AMI ........................................................................S3-2: On
B. B8ZS........................................................................S3-2: Off
3. Network Interface:
A. CSU ........................................................................S3-3: On
S3-4: Off
S3-5: On
NOTE
If the CSU Mode of operation is selected, then the LBO switch must be set as defined
by the carrier. Refer to Switch 2 setting information presented below. If the CSU Mode
is selected, then all the DSX-1 selections are invalid. If the unit is not to be operated as
a CSU but in the DSX-1 mode, then the Transmit Output Pulse must be defined.
DIP Switches: Off = Down Position; On = Up Position