RIO Remote I/O System User Guide
Installing a Long Distance Module (LDM)
Page 187
Chapter 2 Installing hardware and software
Asynchronous/Synchronous Modem & X21bis (DB25 female to DB25 male)Note
Any connector pins not listed in the next table must not be connected.
DB25 female (LDU) DB25 male (Modem)
Pin Signal Description Pin Signal Description
2TXD Transmit Data 2TXD Transmit Dat a
3RXD Receive Data 3RXD Receive Data
4RTS Request To Send 4RTS Request To Send
5CTS Clear To Send 5CTS Clear To Send
7GND Ground 7GND Ground
8DCD Data Carrier Detect 8DCD Data Carrier Detect
15 TXC Transmit Clock 15 TXC Transmit Clock
17 RXC Receive Clock 17 RXC Receive Clock
20 DTR Data Terminal Ready 20 DTR Data Terminal Ready
Leased line
Modem at
host card
site
Modem
at
remote
site
DB25 female to male
adaptor. DB25 female to male
adaptor.
DB25 female flying lead
to remote site LDU
DB25 female flying lead
from host card site LDU