20.008 What are the connections for a standard modem cable?
Description
This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
20.008 What are the connections for a standard modem cable?
The standard modem cable which can support hardware handshaking connects
eight lines between two male Dsub25 connectors:
Seial Port Modem Signal Name
Dsub25m Dsub25m
2 -------- 2 TD (transmit data)
3 -------- 3 RD (receive data)
4 -------- 4 RTS (ready to send)
5 -------- 5 CTS (clear to send)
6 -------- 6 DSR (data set ready)
7 -------- 7 GND (ground)
8 -------- 8 DCD (data carrier detect)
20 -------- 20 DTR (data terminal ready)
There are many variations depending, mainly, upon differences in Serial
Port sockets; and, some lines may be omitted in some cables.
For NULL modem transfers, the Modem side plugs into the NULL modem connector.
By: Tae Song (White Wolf)
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