[CQ-Contest] [SECC] CT-17 Problem

David Pruett k8cc at comcast.net
Mon Sep 12 00:27:36 EDT 2005

At 10:44 AM 9/9/2005, Paul Hansen wrote:
>There is no special RS-232 cable required. Any serial cable should work.

The first sentence is correct.  The second is not completely true.

The cable between a CT-17 and a PC-style serial port should be "straight 
thru" - i.e., not a "null modem" cable which swaps the TXD (TX data) and 
RXD (RX data) pins.

This is complicated by the fact that TXD/RXD are pins 2 and 3 on any PC 
serial port.  However, the actual pins on a DB-9 serial port are reversed 
from a DB-25 serial port, which confuses things.

I would get a null modem adapter (either a 9 or 25 pin) and stick it in and 
see if it helps.  If it does, then you have the wrong kind of cable.

Also, on my CT-17 at least, only the #4 jack seems to work.  It's been that 
way since purchased new in 1989.


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