Don't know for sure if this is the proper forum but it seems like it should be. I just bought a 51A home interphone controller, 3 phones, 3 mikes, and a 730 door answering unit, and I already had some 759 receivers. All were tested except the control unit and found to be working except for some dial issues with the phones. I have spent three days trying to wire them up, and have gained nothing but a loud buzzing or hum from the 759 receivers and 730 receiver. These are the BSPs I have been using to guide me: 512-510-405, 512-510-200, and Section C70.160.01 Issue 4 dated Sept. 1962.
Right off the bat, I thought there was a problem with the wiring as the BSP shows T1 and R1 with BR-W and BL-W pair respectively and T2 and R2 with the W-BR and W-BL pair respectively. When I tested the phones, however, the BL&W pair controlled line 1 and BR&W pair controlled line 2. Even changing the pairs around though did not really make any difference. The T1&R1 terminal is isolated on the interphone terminal board and only serves as a connecting point between the POTS line and line 1 of the phone so I cannot believe BR-W and BL-W could be correct under any circumstances to begin with unless the phone is wired incorrectly.
Any thoughts on where to begin?

Bill