User's Manual

MDS 05-2708A01, Rev. D MDS TransNET I&O Guide 71
Pin Descriptions—RS/EIA-422/485 Mode
Table 28 lists the DATA connector pin functions for radios configured to
operate in RS/EIA-422/485 mode. See Figure 23 for wiring schemes.
NOTES:
• RXD+ / RXA and RXD– / RXB are data sent into the radio to be transmitted out
• RXD+ / RXA is positive with respect to RXD– / RXB when the line input is a “0”
• TXD+ / TXA and TXD– / TXB are data received by the radio and sent to the connected
device
• TXD+ / TXA is positive with respect to the TXD– / TXB when the line output is a “0”
Invisible place holder
Figure 23. EIA-422/485 Wiring Schemes
(Left: EIA-422, Right: EIA-485)
Table 28. DATA connector pin descriptions—RS/EIA-485 Mode
Pin
Number
Input/
Output Pin Description
1—Not Used—Do not connect
2 OUT TXD+/TXA—Non-inverting driver output. Supplies data to
the connected device.
3INRXD+/RXA—Non-inverting receiver input. Accepts data
from the connected device.
4INSleep—A ground on this pin turns off most circuits in a Re-
mote radio, including transmit, receive, modem, and diag-
nostic functions. This allows for greatly reduced power
consumption, yet preserves the radio’s ability to be quickly
brought on line. See “Using the Radio’s Sleep Mode (Re-
mote Units Only)” on Page 59 for details.
5--Signal Ground (GND)—Connects to ground (negative sup-
ply potential) on the radio’s PC board and chassis.
6--Not Used—Do not connect
7INRXD– /RXB—Inverting receiving input
8 OUT TXD– /TXB—Inverting driver output.
9--Open (User configurable via internal jumper. See
“User Configurable I/O Connections” on Page 72)
2-WIRE CONNECTIONS4-WIRE CONNECTIONS
TXD +
RXD +
2
3
7
RADIO
DATA CONNECTOR
8
RXD –
TXD –
EXTERNAL DEVICE
RXD –
TXD +
RXD +
TXD –
RXD+/TXD+
2
3
7
RADIO
DATA CONNECTOR
8
RXD–/TXD–
EXTERNAL DEVICE
RXD –
TXD +
RXD +
TXD –