How To Run RS232 Through Your Walls

Jeff Fisher

db9.gif You've been told that Category 5 (or better) rated twisted-pair cable is capable of handling normal RS232 data...right? But you're wondering how to hook up the DB connectors on your computer and peripheral to the cat5 cable.

gc-a9f2df_1.jpg Well, it's really simple; Just use these adapters and cat 5 patch cables. Assemble the appropriate adapter, plug it into your computer, plug one end of the patch-cable into the adapter, and the other into the cat 5 jack in the wall.

There isn't a standard (to our knowledge) on which cat5 wires go to which RS232 lines, so we just wire them in sequence like this:

RS232 via Cat 5
8P8C Modular Jack Lead Color (Pin #)DB9 Pin #Signal NameSource
Blue (1)1CD - Carrier DetectModem
Orange (2)2RXD - Receive DataModem
Black (3)3TXD - Transmit DataTerminal
Red (4)4DTR - Data Terminal ReadyTerminal
Green (5)5Signal Ground
Yellow (6)6DSR - Data Set ReadyModem
Brown (7)7RTS - Request To SendTerminal
White (8)8CTS - Clear To SendModem

Pin 9 is Frame Ground and is not required.

Note that with a few of these adapters in your toolkit, along with the usual supply of modular plugs, flat cable, and crimp-tool, you can make up your own RS232 cables as needed, always the perfect length!




Newest Blog Posts

  1. A new home.
    2014-10-30 22:44