Question about replacing old style AE TCU with newer one in Chestphone

[RotoTech99]

Dear Forum:

I have a ATC Chestphone with AE components; a TAG-2131B with the older D-8400000 Touch calling unit.. I won't replace the dial if I don't need to, though; and the only thing that would justify it would be is if reversing the red and green line cord leads don't resolve my problem mentioned here.

I have a question about the dial wiring I need help with,  please. I'm thinking of replacing it with a AE 12D Touch calling unit,  which has 1 more lead,  plus, the static shield than the D-8400000A. I'm trying to determine the proper wiring for it,  which I assume,  is, the same as the older pad,  with the exception of the white/black wire which goes to 5 on the transmission network.

My best guess is it's similar to an AE Starlite with the 12D pad,  WA-1154A Network modified for tone dialing,  and terminals *A through D" on the base.  It's been a, while since I've dealt with that type set,  and this Chestphone appears to virtually copy that wiring layout

The diagram for the older dial shows the red handset lead going to 5, will placing the white/black wire there affect anything,  operation wise?

Right now,  the only problem I'm experiencing is polarity reversal,  most likely due to the older dial not having polarity guard circuitry,  I believe.  It gets good dial tone,  and tones when I dial,  aside from not breaking dial tone and polarity reversal.

This is my first tone dial ATC Chestphone with AE internals,  and I like it alot,  having been raised around GTE service areas when I was younger.

I'm pretty sure I'll get an answer that will clarify  and answer my question..if anyone can answer my inquiry,  you have my thanks in advance.

The photo below shows the old style TCU my Chestphone has,  the D-8400000,  dial I believe.

I've never been good with keeping AE part #'s straight in my mind.
Rototech99

[RotoTech99]

I am happy to say I found the answer to my inquiry about using the AE 12D pad to replace the D-84000A TCU in my ATC Chestphone... Amazingly, it is just a couple wires different than the D-840000A; those 2 wires being the static shield (BK),  & dial wire (WH/BK)...  The black static shield wire goes on (2) on the network,  and the WHITE/BLACK wire from the dial goes to (5)  on the network.

This, is, essentially the same wiring used to put a 12D TCU in a early model Starlite phone.  The wiring diagram is in 997-015-800 of the GTE Station Services manual CHB-125; It's page 20 of 22 in the noted section.

As soon as I can scan it to my computer,  I'll put the diagram in with my topic.

Thanks,
Rototech99