Hi, I have an issue with "mating" a nonkey set (2702BM princess) with a separately mounted key 6041G. The BSP for the non-key set is 502-110-102 Fig 10, page 13 click here and the BSP for the separately mounted key is 512-210-103, Fig9, page 7 click here

I had no issue modifying the 2702BM set per the set modification table in the BSP nor do I have any issue with the separately-mounted key. I have 10 of the separately mounted keys working with various types of nonkey sets, and all work just fine. The issue is polarity, since the 2702 does not have a polarity guard and I get the unable-to-break-dialtone issue as when the polarity is reversed. I installed a polarity guard as found here: click but the modified 2702bm doesn't conform to the BSP for the polarity guard since it has a W and a BR lead moved from their normal terminals per the modification chart (W from F to L1 and BR from C to G). As an example, when I placed the polarity guard on the W lead at terminal T on the guard and then put the G lead on F and the BR on the S terminal on the guard and W lead on the guard to the C terminal, I got a short. By removing the guard, I had a dialtone on each of lines 1-5 but couldn't break the dialtone from the touch pad. I swapped ER and ET in the separately mounted key, and, strangely, I was able to break the dialtone and dial out on lines 2-4 but not on lines 1 and 5.

I also found another 2702BM which had a polarity guard installed by WECo, and it behaved exactly as the previously described 2702BM did when I installed a guard myself.

So, the questions are (2) if the 2702BM needs a polarity guard to break the dialtone, where should it be installed since it can't be installed in the normal way, and (2) why doesn't swapping ET and ER in the key (reversing the polarity of the tip and ring) affect only lines 2-4 and not lines 1 and 5 in the same set with the same connections to the separately mounted key.

Of course, this is just a hobby setup, so it isn't like I'm depending on this for livelihood, but I have messed around with this project until I can swap all this out in my head when I'm asleep!

Thanks to anyone who's brave enough to think this through.

Also, hopefully the links will appear on the forum as I embedded them; however, if not, the URL is in the text.

Bill Bentsen

Last edited by Telephonemaven; 11/02/18 04:55 PM.