30 Apr
2010
30 Apr
'10
9:45 a.m.
"Curtis H. Wilbar Jr." wrote:
I have 2 different loopback? plugs... both made by T-BAR
565-980-2 is DB25M with wiring (on the visible circuit side):
2-3
4-5
6-20
8-23
11-15
12-21
14-16
565-980-3 is DB25F with wiring (on the visible circuit side):
13-19-22
17-24
There are traces on the top of the PCB as well, but the DB25
connector is covering them, so they'd have to be discovered via
a multimeter....
I wonder if it is actually the same PCB used on both units, but because of the
mirror-imaging of the pins when they are mounted on the male vs. the female
connector you end up seeing the different sides of the PCB when looking at the
two connectors from the back.
The 'non-typical' pins used make (some) degree of sense for synchronous
operation and the rarely-used secondary channel in the RS-232 standard, e.g.
14-16 == 2ndTXD-2ndRXD
I haven't found any t-bar information by those #s
on line....
And they don't match a few different RS232 loopback plug
wiring diagrams I found online...