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Contents:
Modem Cable Overview
Intel external modems use a DB25S (D-shell, 25-pin female) connector for the RS-232 serial port. The connector on the modem's end of the cable must be a DB25P (D-shell, 25-pin male connector. The connector on the opposite end must mate to the serial port on your computer or terminal.Consult the device's user guide for more information on its connector.
Asynchronous/Synchronous Cable Construction
This diagram shows you how to build a cable good for synchronous and asynchronous communications. Most PCs, however, use RS-232 asynchronous serial ports. For synchronous communications, you must use a synchronous serial port.
NOTE: You must use shielded cable and shielded connector backshells when building the cable.
Modem End
Pin Number |
Signal
Name |
Signal
Direction |
Computer DB25 Pin # |
End DB9 Pin # |
| 1 |
Case Ground |
N/A |
1 |
|
| 2 |
Transmitted Data (TD) |
< |
2 |
3 |
| 3 |
Received Data (RD) |
> |
3 |
2 |
| 4 |
Request to Send (RTS) |
< |
4 |
7 |
| 5 |
Clear to Send (CTS) |
> |
5 |
8 |
| 6 |
Data Set Ready (DSR) |
> |
6 |
6 |
| 7 |
Signal Ground |
N/A |
7 |
5 |
| 8 |
Carrier Detect (CD) |
> |
8 |
1 |
| 15 |
Transmit Data Clock |
> |
15 |
|
| 17 |
Receive Data Clock |
> |
17 |
|
| 20 |
Computer Ready (DTR) |
< |
20 |
4 |
| 22 |
Ring Indicator (RI) |
> |
22 |
9 |
| 24 |
External Transmit Clock |
> |
24 |
| |
2400EX/2400EX MNP/2400E V.42BIS Custom Cable Diagram
Cable specification for connecting to _________________________.
Modem End
Pin Number |
Signal
Name |
SiOther
DiPin |
End Number |
| 1 |
Case Ground |
N/A |
__________ |
| 2 |
Transmitted Data (TD) |
< |
__________ |
| 3 |
Received Data (RD) |
> |
__________ |
| 4 |
Request to Send (RTS) |
< |
__________ |
| 5 |
Clear to Send (CTS) |
> |
__________ |
| 6 |
Data Set Ready (DSR) |
> |
__________ |
| 7 |
Signal Ground |
N/A |
__________ |
| 8 |
Carrier Detect (CD) |
> |
__________ |
| 20 |
Computer Ready (DTR) |
< |
__________ |
| 22 |
Ring Indicator (RI) |
> |
__________ | |
MacIntosh 8-PIN SCC Modem Cable
Cable specification for connecting an Intel external modem to an Apple Macintosh.
NOTE: You must use shielded cable and shielded connector backshells when building cables for this modem.
Modem End
Pin Number |
Signal
Name |
Signal
Direction |
Mac End Number |
| |->1 |
Case Ground |
N/A |
|
| | 2 |
Transmitted Data (TD) |
< |
3 (TX-) |
| | 3 |
Received Data (RD) |
> |
5 (RX-) |
| | 4 |
Request to Send (RTS) |
< |
1 (HSO) |
| | 5 |
Clear to Send (CTS) |
> |
2 (HSI |
| | 6<-| |
Data Set Ready (DSR) |
> |
|
| |->7 | |
Signal Ground |
N/A |
8 & 4 (GND) |
| 8 | |
Carrier Detect (CD) |
> |
|
| 20<-| |
Computer Ready (DTR) |
< |
|
| 22 |
Ring Indicator (RI) |
> |
| |
This applies to:
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