Comtech EF Data CDM-700 - Manual (Page 229)

Appendix B. DUAL E3 / T3 / STS-1
INTERFACE (CDI-10)
B.1 Introduction
The Dual E3/T3/STS-1 Interface (CDI-10) data interface is a plug-in module that inserts into the
rear of the CDM-700 series modem chassis. It provides physical and electrical connection
between the external terrestrial device and the internal circuitry of the modulator or demodulator.
By convention, a modem is Data Communications Equipment (DCE) where Tx data enters the
data interface and Rx data exits. The plug-in interface has full duplex capability.
In addition, the module is automatically configured for simplex-transmit or simplex-receive
operation when the module is plugged into a simplex chassis configured for ‘modulator only’ or
‘demodulator only’ operation. Slot 1 of the modem – located to the right center of the rear panel –
is filled with a data interface module first; Slot 2 – located to the right side edge of the chassis – is
assigned a blank panel or another interface depending upon configurations allowed at time of
order.
Initially, the modem is available in Duplex and Rx only configurations.
The CDI-10 module provides two independent interfaces (ports) that are operable E3/T3/STS-1.
Two primary data interfaces used in the satellite applications are featured:
•
2 independent G.703 Interfaces:
¾ E3, T3, STS-1or OFF
¾ Each separately programmed
•
External Clock Input
Figure B-1 depicts the block diagram of the interface. Figure B-2 shows the module looking at
the rear panel.
A port is defined as a Tx / Rx pair, and there are two independent ports. Assigning each port to a
different data rate is allowed. However assigning the Tx side of Port 1 to a different data rate than
the Rx side of Port 1 is not allowed.
B–1