RJ45 to DB25 Serial Adapter
Posted by rbTech Staff on 05 January 2012 12:35 PM
We recently replaced a dot-matrix printer at a site with an Okidata MicroLine 590. The building is wired with cat-5 that is being used to carry serial signals to the terminals and printers. We needed to build an RJ45 to DB25 (male) adapter to attach to the serial interface on the printer. After digging around for a pinout to make this work, we discovered that the following pinout works:
RJ45 Pin
4 (red)
5 (green)
7 (yellow)
8 (white or gray)
DB25 Pin

Note: Some sites talk about printers being DCE devices, and give a fairly complicated pinout for wiring this adapter. This doesn't seem to be correct - the above pinout should work fine.

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Comments (2)
02 August 2012 10:17 PM
I've been having a hard time discovering a pinout that would work for a Okidata ML395 through a Digi PortServer TS 8. This is running over 50' across my office. I know this can cause problems but our document scanner works just fine. Any ideas about this and flow control, baud rate, etc?
Rubin Bennett
22 August 2012 01:52 PM
It's almost certainly either 9600 8N1 or 38400 8N1. Oki printers are *very* picky about flow control, so you'll need to make sure that your flow control settings between the TS8 and the Oki match. Of course the baud rate must match as well.
For a dirty hack test, you can usually just dump a directory listing to the serial port and it will get printed out:
LInux: ls -l >/dev/ttyts01
Windows: dir >com1

Hope that helps and good luck!
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