56
MDS TransNET 900 I&O Guide
MDS 05-2708A01, Rev. B
Pin Descriptions—RS/EIA-422/485 Mode
DATA
connector pin functions for radios configured to
operate in RS/EIA-422/485 mode. See
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 TXD–/TXB when the line output is a “0”
Invisible
place
holder
Figure 22. EIA-422/485 Wiring Schemes
(Left: EIA-422, Right: EIA-485)
Table 20. DATA connector pin descriptions—RS/EIA-485 Mode
Pin
Number
Input/
Output
Pin Description
1
—
Not Used—Do not connect
2
OUT
TXD+/TXA (Received Data +)
Non-inverting driver output.
3
IN
RXD+/RXA (Transmitted Data +)
Non-inverting receiver input.
4
IN
Sleep (GND = Active)—A ground on this pin turns off most
circuits in the radio, including transmit, receive, modem, and
diagnostic functions. This allows for greatly reduced power
consumption, yet preserves the radio’s ability to be quickly
brought on line. See Section 5.6, Using the Radio’s Sleep
Mode (beginning on
5
IN
Signal Ground (GND)
Connects to ground (negative supply potential) on the ra-
dio’s PC board and chassis.
6
--
Not Used—Do not connect
7
IN
RXD–/RXB (Transmitted Data –)
Inverting receiver input.
8
OUT
TXD–/TXB (Received Data –)
Inverting driver output.
9
--
Reserved for Special Uses (Do not connect)
TXD +
RXD +
2
3
7
DA
T
A
CONNECT
OR
8
RXD –
TXD –
4-WIRE CONNECTIONS
RXD+/TXD+
2
3
7
DA
T
A
CONNECT
OR
8
2-WIRE CONNECTIONS
RXD–/TXD–
Содержание EL805
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