CA-48s can only go on Ext. 10 and 11. By default, it will have all the extensions already programmed starting in the upper left as Ext. 10, going down the column and then over from there. They are programmed as RINGING intercom buttons, if you want Voice Announce, you will need to reprogram them as Intercom *-XX. If you have put any Auto-Intercom buttons on the 34-D, those extensions will be blanked out on the CA-48 when you plug it in, so you will probably want to put them back.
The buttons are all programable, but only as Auto Intercoms (can't put features or speed-dials on them.) Programming is the same as on the set, FEATURE 00, press a button on the CA-48, Left INTERCOM, then dial the Ext. No. or * and the Ext. No.
Units comes with a Power Cube and a special splitter. The splitter goes in the jack, a short modular cord with a special end goes from the power cube to one side of the splitter, an 8-conductor line cord goes from the other side of the splitter to the "IN" jack of the CA-48, and the regular 4-conductor line cord goes from the "OUT" jack of the CA-48 to the "LINE" jack of the Partner set.
Pay attention to the markings on the splitter, which indicate which side gets the Power cord, and which side get the Line cord. I've seen several where the stickers were reversed.
