This section lists the PMBX & PABX systems. The data comes from the Post Office Telephones, Service Instruction manuals TPSI (S.S.479A)

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House Exchange Systems
Cordless PMBX (Indicator Signalling
Cordless PMBX (Lamp Signalling)
25 Line Corded PMBX 5+20 (Indicator Signalling)
65 Line & 80 Line Corded PMBX (Indicator Signalling)
Private Manual Branch Exchange (PMBX)
Private Automatic Branch Exchange (PABX)
Corded PMBX 4 (Lamp Signalling)
Corded PMBX 1A & 1B (Lamp Signalling)
Corded PMBX CB9 (Indicator Signalling)
Corded PMBX BECB 10 (Lamp Signalling)
Police Telephone & Signal Systems (PA150 & PA450)
PABX No 1
PABX No 2
PABX No 3
PABX No 4
PABX No 5
PABX No 6
Comparison Of The Merits Of PABX 3 & 4
Private Meters On PBX's
Guidance On  PABX 3 Proposals