What two pins are used on Command Base?

I believe it's pin 2 & 3.

Hopefully someone will chime in soon with corrections if this is wrong.

You may want to move this to the TMCC-Legacy forum to get more coverage.

Rod

It would be transmit data and ground, pins 3 and 5.  It's a "write-only" interface, so the read isn't used.

To clarify, the Base certainly will respond to incoming TMCC serial commands.  The interface to the ASC is of course one-way only.

Correct, I was simply answering the question about the ASC cable.  I should have been more clear in the reply.

Hi John,

 Both an ASC 3000 amd Sc-2 should arrive today in the mail.

Based on on the  standard DB-9 pinout diagram, logic, and your confirmation of what I had decided, I was either about to make a mistake or the original IC controls manual is incorrect. But  I am also learning slowly that not everything in this hobby makes sense or follows standards. Of course Lionel does not even discuss making your own cable. They would rather sell you theirs.





opps, accidently loaded the wrong file

It all depends on whether you are describing the connection in terms of DTE (Data Terminal Equipment) and DCE (Data Circuit-terminating Equipment).

Since I appears that the base is considered DCE and not DTE, the transmit and receive designations would be swapped.  Here's a table handy showing the direction of the signals for DCE vs. DTE equipment.

Given that fact, it's actually pin 2 and pin 5.   You'll notice the output from a DCE device is on pin 2, Receive Data.

So it likes like it is pin 2 (red) and pin 5 (green).

Assuming the command base is acting like a  modem and transfering to the controller (computer) that makes sense. No feedback to the command base. All memory/ settings stored on the individual controllers similar to engine ids.

Sounds right to me.   I know they don't talk back.

If you are going to go to the trouble of making your own TMCC cable you might as well make the three pin type. That way if you ever install an Action Recorder Controller you won't have to remake the cable.  I'll open up one of my cables and see what pin you use. I know you use the black wire that is inside the cable.