25-pos. Screw
Direction
Name
Description
D-sub
Terminal
DCE-DTE
1
- - -
PE
Protective earth
2
8
TXD
Transmit data
3
7
RXD
Receive data
4
6
RTS
Request to send
5
5
CTS
Clear to send
6
2
DSR
Modem ready
7
1
- - -
SG
Signal ground
8
4
DCD
Data carrier detect
9
Continuous high
10
Continuous low
12
DRS
Speed indication (1200/2400)
15
TXC
Synchronous TXD clock from modem
17
RXC
Synchronous RXD clock from modem
20
3
DTR
Data terminal ready
21
RDL
Request of remote digital loop back
22
9
RI
Ring indicator
23
DRS
Data speed select (1200/2400)
24
EXC
External synchronous clock
25
TI
Test indication signal
7
6178-2203
RS-232/V.24 Connections
Pin outs for the 25-pole D-sub and 9-pole screw terminal:
The other pins in the 25-pole D-sub should be left unconnected.
←
←
←
←
←
←
←
←
←
←
←
←
←
←
←
←
←
Line connection
The telephone line is connected to the 6-pole RJ-12
connector or to the 4-pole screw block in the bottom
left side.
When using the screw-block a strap plug supplied must
be placed in the RJ-12 connector.
If this is not done the outgoing signal will not be
connected to the screw-block.
1
:
6
1 2 3
4
2-wire lines are connected to the two middle pins (3 & 4)
in the RJ-12 plug or the TX screws (1 & 2).
In the UK modems the 2-wire line is connected to pin 2 & 5
in the RJ-12 connector.
4-wire lines are connected to the screw terminal, transmitter
to TX (1 & 2) and receiver to RX (3 & 4).
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