User's Manual

14 MDS SD4 Startup Guide 05-4669A01, Rev. B

COM2 CONNECTIONS

The COM2 connector (Figure 10) is used to connect the radio to an

external DTE telemetry device that supports the EIA/RS-232 or

EIA/RS-485 (balanced) format, depending on how the radio is config-

ured. The radio supports data rates of 300, 1200, 2400, 4800, 9600,

19200, 38400, 57600, and 115200 bps (asynchronous data only).

The

COM2 connector mates with a standard DB-9 plug that is avail-

able from many electronics parts distributors. Table 5 provides

detailed pin descriptions for the

COM2 data connector in RS/EIA-232

mode.

NOTE:To prevent unintended keying of the transmitter on RTS, set

RTSKEY to OFF, or do not connect to Pin 7 (RTS) of the COM2 port.

Pin Descriptions—RS/EIA-232 Mode

Table 5 lists the COM connector pin functions when configured to

operate in RS/EIA-232 mode. For RS/EIA-422/485 mode, refer to the

Reference Manual.

NOTE: The radio is hard-wired as a DCE device.

Figure 10. COM2 Connector (DB-9F)

As viewed from outside the radio

Table 5. COM2 Pin Descriptions—RS/EIA-232

Number

Input/

Output Pin Description

1 OUT DCD (Data Carrier Detect/Link)—A low indicates

signal received.

Digital Modem Selections: Digital carrier detect

Analog Modem Selections: Squelch indicator

2 OUT RXD (Received Data)—Supplies received data to

the connected device.

3INTXD (Transmitted Data)—Accepts TX data from the

connected device.