Multi-Tech Systems MTCBA-E1 ユーザーズマニュアル
Chapter 1 – Product Description and Specifications
12
Multi-Tech Systems, Inc. MultiModem Cell User Guide
9-Pin Fem-D Sub Serial Connector
The following table explains the pin functions.
DE9 Pin Assignment
Female Connector
DE9
Pins
Pins
RS232 Signals
DCE
DCE
RS422 Full
Duplex Signals
Duplex Signals
Signal
Direction
Direction
Pin 1
Data Carrier Detected (DCD)
RxD-
Out
Pin 2
RXD
RxD+
Out
Pin 3
TXD
TxD+
In
Pin 4
Data Terminal Ready (DTR)
TxD-
In
Pin 5
Ground
Ground
N/A
Pin 6
Data Set Ready (DSR)
Ready To Send -
(RTS-)
(RTS-)
Out – RS232
In – RS422
In – RS422
Pin 7
Ready To Send (RTS)
Ready To Send +
(RTS+)
(RTS+)
In
Pin 8
Clear To Send (CTS)
Clear To Send +
(CTS+)
(CTS+)
Out
Pin 9
Ring Indicator (RI)
Clear To Send -
(CTS-)
(CTS-)
Out
Note:
The DSR signal on pin 6 is always asserted by the modem.
4-Position DIP Switch
Switch Position
Up/On
Down/Off
Down/Off
Description
Position 1
Off
DTR Reset Disabled
Position 1
On
DTR Reset Enabled
Positions 2-4
Only valid for serial builds
Position 2
Off
No TXD Termination
Position 2
On
TXD Diff Pair Terminated
Position 3
Off
No RTS Termination
Position 3
On
RTS Diff Pair Terminated
Position 4
Off
RS232 Mode
Position 4
On
RS422 Mode
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.
maximum may be more with termination enabled and lower data rates.