Electrical Interface - Comtech EF Data CDM-550T Manual

Async Overhead Option

Electrical Interface

The electrical interface is 3-wire EIA-232 (Rx Data, Tx Data, and ground). No flow control is
provided. The async character format is fixed at 8 data bits, no parity, 1 stop bit, (8-N-1), full
duplex.
Pin Numbering
Looking at the rear panel, pin 1 is on the right-hand side:
Baud Rates
The main channel data rate versus async channel baud rate is as follows:
All modes except 21/44 and 5/16 Turbo:
<50 kbps - option disabled
50 to 99.999 kbps – 1200 baud
100 to 199.999 kbps – up to 2400 baud
200 to 399.999 kbps – up to 4800 baud
>399.999 kbps – up to 9600 baud
(Rate 1/2 BPSK modes are limited to 4800 at rates above 550 kbps)
21/44 and 5/16 Turbo modes:
<150kbps - option disabled
150 to 299.999 kbps – 1200 baud
300 to 599.999 kbps – up to 2400 baud
>599.999 kbps – up to 4800 baud
C–2
Rx D Gnd Tx D
(Input) (Output)
• • • • • • • • • • • •
Pin 1
CDM-550T Satellite Modem
Rev. 1.3