Comtech EF Data CSAT-6070 - Manual (Page 75)

Appendix A. REMOTE CONTROL
A.1 Introduction .................................... A–1
A.2 Basic Protocol ................................ A–2
A.3 Commands or Responses ............. A–6
A.1 I
NTRODUCTION
This document describes the protocol and message repertoire for remote monitor and control of
the CSAT Outdoor terminal.
The electrical interface is either an EIA-485 multi-drop bus (for the control of many
devices) or an EIA-232 connection (for the control of a single device), and data is
transmitted in asynchronous serial form, using ASCII characters. Control and status
information is transmitted in packets, of variable length, in accordance with the structure
and protocol defined in later sections.
A.1.1 EIA-485
The EIA-485 interface is provided at the 19-pin circular J5 connector. The interface is a 4-wire
EIA-485 interface using the pin out shown in the table below. Since a half-duplex
communication protocol is used, the +Tx and +Rx as well as the –Tx and –Rx signals can be tied
together at the user end to support a 2-wire interface. The EIA-485 driver is only active during
transmission and is tri-stated when not is use.
Table A-1. EIA-485 Interface
Pin Signal Name I/O Notes
A EIA--485 +Rx Input CSAT Receive line
B EIA--485 –Rx Input CSAT Receive line complement
C EIA--485 +Tx Output CSAT Transmit line
D EIA--485 –Tx Output CSAT Transmit line complement
T Ground Passive
A.1.2 EIA-232
The EIA-232 interface is provided at the 19-pin circular J5 connector. The interface provides the
five signals shown in the table below. The CSAT only requires three wires (TD, RD, and
Ground), the other two signal are provided for terminal equipment that requires RTS/CTS
handshaking. The CSAT simply ties these two signals together.
A–1