Systech Corporation NDS/5000, Hardware Manual

Page: 22 / 39

Connecting Devices to the NDS 16
DB-9 Pin
Number
DB-25 Pin
Number/Signal
1 DCD
9 RI
8 CTS
7 RTS
6 DSR
5 GND
4 DTR
3 TX
2 RX
8 DCD
22 RI
5 CTS
4 RTS
6 DSR
7 GND
20 DTR
2 TX
3 RX
Figure 2-11: DB-9 to DB-25 Modem Cable
DB-9 Pin
Number
DB-9 Pin
Number
1 DCD
9 RI
8 CTS
7 RTS
6 DSR
5 GND
4 DTR
3 TX
2 RX
4 DTR
9 RI
7 RTS
8 CTS
5 GND
1 DCD
2 RX
3 TX
6 DSR
Figure 2-12: DB-9 to DB-9 Terminal Cable
The NDS/6000 does not require the use of all 9 wires. Only the RX, TX, and GND signals are
essential. DTR/DSR and RTS/CTS are only necessary for flow control. DCD (pin 1) is
normally not required and RI (pin 9) is only required for modems that need a ring indicator.
Figure 2-13 shows a minimal 3-wire cable using only RX (pin 2, data in), TX (pin 3, data out),
and GND (pin 5, ground).