9-Pin Fem-D Sub Serial Connector; 4-Position Dip Switch - Multitech MultiModem Cell MTCBA-E1 User Manual

Chapter 1 – Product Description and Specifications

9-Pin Fem-D Sub Serial Connector

The following table explains the pin functions.
DE9 RS232 Signals
Pins DCE
Pin 1 Data Carrier Detected (DCD)
Pin 2 RXD
Pin 3 TXD
Pin 4 Data Terminal Ready (DTR)
Pin 5 Ground
Data Set Ready (DSR)
Pin 6
Ready To Send (RTS)
Pin 7
Clear To Send (CTS)
Pin 8
Ring Indicator (RI)
Pin 9
Note: The DSR signal on pin 6 is always asserted by the modem.

4-Position DIP Switch

Switch Position
Position 1
Position 1
Positions 2-4
Position 2
Position 2
Position 3
Position 3
Position 4
Position 4
Note: Positions 2 and 3 should only be used in RS422 Mode. Enabling TXD/RTS termination may be required to
avoid errors at high bit rates or long cable lengths. Multi-Tech Systems tested the cable up to 1,000 feet , but the
maximum may be more with termination enabled and lower data rates.
12
DE9 Pin Assignment
RS422 Full
Duplex Signals
RxD-
RxD+
TxD+
TxD-
Ground
Ready To Send -
(RTS-)
Ready To Send +
(RTS+)
Clear To Send +
(CTS+)
Clear To Send -
(CTS-)
Up/On
Description
Down/Off
Off DTR Reset Disabled
On DTR Reset Enabled
Only valid for serial builds
Off No TXD Termination
On TXD Diff Pair Terminated
Off No RTS Termination
On RTS Diff Pair Terminated
Off RS232 Mode
On RS422 Mode
Signal
Direction
Out
Out
In
In
N/A
Out – RS232
In – RS422
In
Out
Out
Multi-Tech Systems, Inc. MultiModem Cell User Guide
Female Connector