_______________________________________________________________
Computer | Modem |
---|---|
DTE | DCE |
25p--9p | 25p |
2 -- 3 | TXD------ 2 |
3 -- 2 | RXD------ 3 |
4 -- 7 | RTS------ 4 |
5 -- 8 | CTS------ 5 |
6 -- 6 | DSR------ 6 |
7 -- 5 | GND------ 7 |
8 -- 1 | DCD------ 8 |
20 -- 4 | DTR------ 20 |
22 -- 9 | RI------- 22 |
---------------------------------------------------
LapLink Serial Cable | Parallel Cable LapLink MS-DOS Link | |
---|---|---|
25pin--9p | 9pin | |
1 -- 1 | ||
RXD 3 -- 2 | 3 TXD | 2 -- 15 |
TXD 2 -- 3 | 2 RXD | 3 -- 13 |
DTR 20 -- 4 | 6 DSR | 4 -- 12 |
GND 7 -- 5 | 5 GND | 5 -- 10 |
DSR 6 -- 6 | 4 DTR | 6 -- 11 |
RTS 4 -- 7 | 8 CTS | 10 -- 5 |
CTS 5 -- 8 | 7 RTS | 11 -- 6 |
12 -- 4 | ||
13 -- 3 | ||
14 -- 14 | ||
15 -- 2 | ||
16 -- 16 | ||
17 -- 17 | ||
25 -- GND -- 25 |
---------------------------------------------------
BASIC RS-232 | IBM-->Centronics | |
---|---|---|
(DCE perspective) | 25pin--36pin | |
IEEE-P1284-A/B | ||
1 -- strobe -- 1 | ||
1 FG frame ground | 2 -- D0 -- 2 | |
2 -> TD transmit data | 3 -- D1 -- 3 | |
3 <- RD received data | 4 -- D2 -- 4 | |
4 -> RTS request to send | 5 -- D3 -- 5 | |
5 <- CTS clear to send | 6 -- D4 -- 6 | |
6 <- DSR data set ready | 7 -- D5 -- 7 | |
7 SG signal ground | 8 -- D6 -- 8 | |
8 <- DCD data carrier detect | 9 -- D7 -- 9 | |
20-> DTR data terminal ready | 10 -- ack -- 10 | |
0 = +3 to +15V | 11 -- busy -- 11 | |
1 = -3 to -15V | 12 -- paper -- 12 | |
13 -- select -- 13 | ||
14 -- alf -- 14 | ||
15 -- error -- 32 | ||
16 -- init -- 31 | ||
17 -- select -- 36 | ||
18-25-GND--- |
---------------------------------------------------
9-pin,female | 25-pin, male |
---|---|
Connector | Connector |
1 Data Carrier Detect | 8 |
2 Receive Data | 3 |
3 Transmit Data | 2 |
4 Data Terminal Ready | 20 |
5 Ground | 7 |
6 Data Set Ready | 6 |
7 Request To Send | 4 |
8 Clear To Send | 5 |
9 Ring Indicator | 22 |