"J.B. Wood" writes:


Now in "ancient" times two-party line ringing was accomplished by
........................Bell's
connecting the phone's ringer from Tip-to-earth ground on one
subscriber's set and from Ring-to-ground on the other subcriber's set.
This also had to be wired appropriately on the central office's ringing
equipment. Connecting subscriber set ringers in this manner adds a very
slight amount of hum due to the unbalancing of the phone line (but not
much due to the ringer coil high impedance).

Unless it was a long rural loop, which was where you found many party lines...
Then the hum was an issue.

AFAIK all ringing these days is bridged (ringer connected Tip-to-Ring)
so ringing-to-ground would probably not work. This is also worth
remembering if you ever desire to hook-up an antique phone (e.g. a WE
type 500 or 2500 set) to your phone line and find the ringer
non-operative (unless you want it that way). The ringer should be
connected to the incoming phone line red and green wires with no ringer
wire connected to the yellow or black one. Sincerely,

NotBell used tuned ringers; there were FOUR plans, as I recall:

20, 30, 40, 50 Hz
22, 33, 44, 55
16.66, 33.33, 50, 66.66
16, 30, 42, 54, 66

I can no longer remember all the names....

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433