B.2 Adpcm Voice Interface; B.2.1 Theory Of Operation; Figure B-2. System Interface Diagram - Comtech EF Data SDM-100A Installation And Operation Manual

Options

B.2 ADPCM Voice Interface

The ADPCM voice interface is capable of providing a single duplex voice channel and
Ear and Mouth (E&M) signaling data transmission. The interface also provides an EIA
STD RS-422 interface which is user selectable. This optional interface replaces the RS-
422, RS-232, or V.35 interfaces.

B.2.1 Theory of Operation

The ADPCM interface is designed to simulate either a trunk or a subscriber circuit.
(Refer to Figure B-2.) The E&M circuitry supports types 1 to 5. Trunk or Subscriber
configuration and E&M signaling type are user selectable from the front panel in the
CONFIG INTERFACE menu.
Refer to Figure B-3 for a modem block diagram with the ADPCM voice interface option.
(Configured as a Subscriber.)
M
Trunk
E & M
E
B–12
SDM-100A
MUX MOD
DMUX DMOD

Figure B-2. System Interface Diagram

SDM-100A Satellite Modem
SDM-100A
(Configured as a Trunk.)
DMOD DMUX
E & M
MOD MUX
M
SUB
E
Rev. 0