Those familiar with this system know the system uses four pairs in a USOC configuration. Pairs 1 to 3 are tip/ring. The fourth pair carries DC to power the phones and is also used for Intercom, Paging and various signalling functions.
I have been installing a used system and had no power supply. I figured any good 24 VDC supply should work.
No such luck, the power supplies I tried powered the phones just fine, but the communication channel on the 4th pair would only work if I physically disconnected the power supply from the shared pair (and the phones were therefore working on their backup batteries). Under these circumstances all worked just fine.
Buying DBA's power supply wasn't a good option due to cost.
After thinking about this for a bit I realized that the digital data was being filtered out by the output capacitors in the power supply.
How to keep the high frequency digital stuff out of the power supply? Some sort of coil on the two power supply leads is the answer, but I tried winding some wires on a toroids and no go.
I finally found a simple answer. In my junk box was a Corcom AC line filter as used at the AC inlet on many products. I put this in series with my DC power leads and all is fine!
That saved me some bucks and getting this system up will make my wife happy.
I have been installing a used system and had no power supply. I figured any good 24 VDC supply should work.
No such luck, the power supplies I tried powered the phones just fine, but the communication channel on the 4th pair would only work if I physically disconnected the power supply from the shared pair (and the phones were therefore working on their backup batteries). Under these circumstances all worked just fine.
Buying DBA's power supply wasn't a good option due to cost.
After thinking about this for a bit I realized that the digital data was being filtered out by the output capacitors in the power supply.
How to keep the high frequency digital stuff out of the power supply? Some sort of coil on the two power supply leads is the answer, but I tried winding some wires on a toroids and no go.
I finally found a simple answer. In my junk box was a Corcom AC line filter as used at the AC inlet on many products. I put this in series with my DC power leads and all is fine!
That saved me some bucks and getting this system up will make my wife happy.
