Receives calls but dial pad has no tones. There are two wires with factory ends that were taped off coming out of the keypad (orange and lavender) I don't know if that has anything to do with the problem. Any input would be great.

Anyone have a wiring diagram? Have to tried cleaning the dial contacts?

OK, here you go. This is for the -DM configuration, but since I doubt you will need A-leads, this should be all that you need:

Dial leads:

OR/BK: Network terminal C with brown switchook lead;

GN: Network terminal F with white switchook lead;

BK: Network terminal RR;

RD/GN and WH: Network terminal R with red switchook lead;

BL: Network terminal B with black handset lead;

WH/BL: Network terminal S (or any blind terminal) with green handset lead and black switchook lead;

RD: Network terminal T (or any blind terminal) with red handset lead;

Other connections:

WH lead from handset: Network terminal GN;

GN lead from switchook: Network terminal L1 with green line cord lead and black ringer lead;

YL and SL leads from switchook: Network terminal L2 with red line cord lead and red ringer lead.

SL lead from ringer coil: Network terminal K;

SL/RD lead from ringer coil: Network terminal A

***Insulate and store the following dial leads separately***

GN/WH
VI
OR

Have you got the polarity correct?

-Hal

Sorry to confuse the issue, but I do have the BSP pages for the 2500M / 2500MM / 2500MMG and they differ from what Ed posted. I can PM or post a 6 page PDF, but basicilly I show the following for the 2500MM:

Dial leads:

OR/BK: Network terminal C with white switchook lead;

G: Network terminal F with ringer B and green line cord lead ;

BK: Network terminal RR;

RD/GN: Network terminal R with black switchook lead and handset W;

W: Network terminal GN;

BL: Network terminal B with black handset lead;

WH/BL: Network terminal S (or any blind terminal) with green handset lead and red switchook lead;

RD: Network terminal T (or any blind terminal) with red handset lead;

Other connections:


GN lead from switchook: Network terminal A with red line cord lead;

YL lead from switchook: Network terminal G with yellow line cord lead.

BR lead from switchook: Network terminal L1 with black line cord lead.

RD lead from ringer coil: Network terminal K;


***Insulate and store the following dial leads separately*** (Wires not shown on my print)

GN/WH
VI
OR

Note that the White and Blue Line cord leads were optional connections to the ringer and normally taped off.

PDF file available at:

https://www.jknichols.net/db5/00440/jknichols.net/_uimages/2500M.pdf

That is not a problem at all and you certainly are not confusing the issue. I was just recalling the -DM equivalent (non-A lead) wiring from memory. Thanks for posting the real stuff.

By the way, I suspect that the dial was replaced at some point with a speakerphone-compatible one and the spare switching leads were just insulated and stored. I'm sure that's why they didn't show up in your diagram.

Also, the 2500MM originally had a type 35 dial that WAS polarity sensitive, but could be upgraded to a 2500MMG with a type 71 dial that did not care about polarity - can you find a code number on the dial with either 35 or 71 in it?

Correct me if I'm wrong, but I think that the Red (ring) wire should be negative 48 volt relative to ground and the Green (tip) wire should be close to Ground

That's correct but the easy way to check is to just reverse them (T&R).

-Hal

2500 mm

https://www.porticus.org/bell/images/bsp/2500mm_fig2.gif

Several years ago we used a "polarity guard" on a customer's 2500 set that was plugged into an extension port on a Picazo system.

https://www.ericofon.com/catalog/parts/pg.htm

https://www.oldphoneworks.com/polarity-guard.html