User guide

24
Canoga Perkins
RS-232C RS-423/CCITT
pin mnem signal name mnem signal direction
1 FG Frame Ground FG 101 n.a.
2 TXD Transmit Data SD 103 to modem
3 RXD Receive Data RD 104 from modem
4 RTS
1
Request To Send RS 105 to modem
5 CTS
1
Clear To Send CS 106 from modem
6 DSR Data Set Ready DM 107 from modem
7 SG Signal Ground SG 102 signal ground
8 DCD
1
Data Carrier Detect RR 109 from modem
11
2
LT Local Loopback Test to modem
15 SCT Serial Clock Transmit ST 114 from modem
17 SCR Serial Clock Receive RT 115 from modem
18
2
RT Remote System Test to modem
24 SCTE Tx External Clock TT 113 to modem
1 - Only Local Handshake is supported
2 - The 2270 & 2290 Modems include a built-in Loopback Test feature. Two normally undefined lines (RS-232C pins 11 and 18)
are used for interface control of these system test functions. Refer to Chapter 5, "Troubleshooting," for a more thorough
description of this feature.
Table 3-B. RS-232C/423 Signals and Pin Assignments
Table 3-C. Available Models of RS-449/422 Interfaces
Model Description
-22 RS-449/422 (RS low)
-H22 RS-449/422 (RS high)
-R2R RS-449/422 (balanced CTS, RS
low)
3.3.1 Jumper Strap Settings
Jumper Strap Position Function
W1/W2 W1 Chassis GND tied to Sig GND through 100 ohms
W2 W2Chassis GND tied directly to SIG GND
W3/W4 W3 RTS biased to "ON"
W4 RTS biased to "OFF"
Table 3-A. Jumper Strap Settings