11
4.2 CONNECTING THE MODEL 1089/C (V.35) SERIAL INTERFACE
Model 1089/C supports V.35 serial port connections. This section
describes how to connect the serial ports to your V.35 equipment.
4.2.1 Connecting the Model 1089/C (V.35) to a “DTE” Device
The Model 1089/C provides a V.35 DCE (Data Circuit Terminating
Equipment) interface on an M/34 female connector. As a DCE, this
interface is designed to connect to DTE equipment, such as a router.
When connecting the V.35 interface of the Model 1089/C to your DTE
device, use a V.35
straight through
cable (See Figure 4, below).
Appendix C
describes pin assignments and signal sources for the
Model 1089/C V.35 interface. When purchasing or constructing an
interface cable, please refer to the pin diagrams in
Appendix C
as a
guide.
4.2.2 Connecting the Model 1089/C (V.35) to a “DCE” Device
The Model 1089/C provides a V.35 (Data Circuit Terminating
Equipment) interface on an M/35 female connector. As a DCE, this
interface is designed to connect to DTE equipment, such as a router.
However, tail-circuit applications require connection to another DCE
equipment, such as a multiplexer. When connecting the V.35 interface
of the Model 1089/C to your DCE device, use a V.35 null modem
cable. Some applications may also required the installation of a V.35
tail-circuit buffer to account for small differences in clock frequency
between the 1089/C and the V.35 DCE (multiplexer).
4.3 CONNECTING THE MODEL 1089/D (X.21) SERIAL INTERFACE
Model 1089/D supports X.21 serial port connections. This section
describes how to connect the serial ports to your X.21 equipment.
4.3.1 Connecting the Model 1089/D (X.21) to a “DCE” or “DTE”
Device
The Model 1089/D provides an X.21 interface on a DB-15 female
connector. The X.21 interface default configuration is DCE (Data
Circuit Terminating Equipment) for connection to DTE (Data Terminal
Equipment) such as a router. However, the X.21 interface on the
Model 1089/D may be configured as DTE (Data Terminal Equipment)
for connection to DCE such as a modem or multiplexer. When con-
necting the X.21 interface of the Model 1089/C to your DTE device,
use a X.21
straight through
cable (See Figure 6, below).
To modify the DCE/DTE orientation from the default position
(DCE), you must open the Model 1089/D case.
4.3.1 Opening the Case
To open the Model 1089/D case, insert a flat head screw driver
into an open slot on both sides of the case, as in Figure 7. Twist the
screw driver head slightly and the top half of the case will separate
from the lower half, as in Figure 7, below. Take caution not to dam-
age of the pc-board mounted components.
12
Figure 4.
Connecting the Model 1089/C to V.35 Serial DTE
Figure 5.
Connecting the Model 1089/C to V.35 Serial DCE
Straight-Through M/34
Cable
DSL Span
Model 1089/C (DCE)
Remote Model 1089)
Router (DTE) with V.35
Serial Interface
Figure 6.
Connecting the Model 1089/D to X.21 DTE or DCE
Straight-Through 15-pin
D-Sub Cable
DSL Span
Router (DTE)
OR
Mux (DCE)
Model 1089/D (DCE or DTE)
Remote Model 1089)
Figure 7. Opening the 1089 Case with a Small Screwdriver
DSL Span
Remote Model 1089
Model 1089/C (DCE)
V.35 Multiplexer (DCE)
