Over here 48-58 V is normal... the lower voltages are mentioned as telephones should be designed to cope with those conditions.. e.g. some PABXs etc can provide weird voltages.
As for the ring cadence...
In the early 1990s we had 2 lines from two different switches in the house.
1 was AXE
the other was ARF (Crossbar)
(The AXE was actually providing trunk access etc for the ARF which was gradually, cut over to AXE one number range at a time )
The phone on the ARF line had a noticably slower ring signal.
Phoning out on the ARF was weird too.
You tone dialled the number and then got, what appeared to be a specifically generated tone which sounded like "tick-tick-tick-tick-tick-tick-tick" rather than just random switch noise and then a big "CLUNK" as it made the connection. Occasionally you'd over-hear a blast of MF tones as it signaled either internally or to its parent AXE.
The weird thing is that I used to get better modem speed on the ARF than on the digital AXE line
" Ericsson was always the great innovator with R2. In their ARF crossbar system, they used MFC (MF Compelled) to signal from the register to the individual switch markers and this too could work end to end, so these markers all appeared to act like small transit registers."
The switch wasn't supposed to let you hear this but occasionally you would hear blasts of tones...
Part of the reason for the E10 (digital switch) routing tone was to hide the in-band signalling used when talking to ARF switches.
Eircom actually developed a system in-house called "BOB" to monitor these tones and provide a full PC interface to the exchange for testing and improvements to itemised billing. ARF had to be able to handle non-unit based billing.
BTW since the early 1980s, there was no way for an ARF to communicate directly with the rest of the network they were always "parented" by an AXE or E10 switch that handled their incomming/outgoing traffic digitally. (i.e. using C7 / SS7).
ARFs are now long gone from the network.
[This message has been edited by djk (edited 01-11-2004).]