The wiring is a 'loop' system feeding the left & right side of the building. (2 cables, 1 for either side) The 'loop' system serves as a single cable supplying 4 apartments (4 apartments on the left side), and the same on the other (4 apartments on the right side). My goal (if possible) is to simply replace the old 8-way Intercom system with a new unit, using the existing 8 internal handsets, using the existing wiring, and using the existing latch/door-release. The incoming wiring has red, blue (x2, for 2-way speech I presume), brown, grey (or at least it now looks grey after 20 or so years) and orange wires. The orange one goes to a single terminal (B) and then carries on to two other terminals (F and G). The others all go to single terminals. So... The other coloured wires are present, but i now know that they feed the other apartments (see next point, Cabling).

x aforementioned circuit cables (looping either side of apartment building), each side using 4 coloured wires (1 wire for each apartment) & common red. It had a speech unit (which allowed the 'resident' to hear the 'guest/visitor', and I assume the other way as well, perhaps?). Can anyone help me to identify which wires go where (Z T 0 R 1) on the new handset? Please see the images which include the existing wiring (photo and diagram) at //www.diynot.com/network/DIYJunkie/albums/ The kit comes complete with the 801 handset, which is one of the most popular handsets in the UK. Built from ABS plastic it is highly durable and with its smooth finish it is easy to keep clean. It is possible to have up to three handsets per button if required. I've just bought a replacement handset (Bell 801) for my door entry system. The existing phone that I'm replacing has 5 wires going to different parts of the handset but their destinations are marked A B C etc. It appears to be an old "Entryphone" handset

Unfortunately, but unsurprisingly, the new unit didn't come with any wiring schematics - or indications that it required 4+1 wires. The grill covering the speech unit does not compromise audio quality, and the speech unit is securely fixed to the rear of the plate, making for a great door entry system.

In addition to the unit literally falling apart, the main issue was the fact that the caller couldn't hear the voice of the resident (using the handset in the apartment) while standing at the external Intercom (building entry door at street level). This issue increased the higher the apartments (the further away they were from the Intercom at street level). I should also point out the old handsets have an internal 'buzzer' within them, which buzzes when a visitor presses the Intercom. However, upon installing it and trying to mimic the original wiring (from observing the original Intercom & speech module), it became clear that i needed more wires than i have (2 wires from each apartment) : ( One of the most popular kits on the market, the Bell 901 kit features a high quality intercom panel manufactured from 3 mm anodised aluminium with a brushed finish.Please note: this item is no longer available and has been discontinued. Please use XL5-PS as a direct replacement. ** Posting in this forum as my 'issue' is similar to the OP - and desperately hoping for a swift reply.