Types of Ringers ?

[Dan/Panther]

I have some literature compliments of Mike Neals website, and in there Kellogg  talks about 3 types of ringers.
1) Biased
2) Harmonic
3) Straight Line.
Exactly what are the three, and their differenecs ?
D/P

[Bill]

In a biased ringer, the clapper at rest is held aginst one of the gongs, rather than centered in the space between the gongs. It is a way of selectively ringing one party on a party line. Try to wade through the discussion at
http://www.classicrotaryphones.com/forum/index.php?topic=111.0

In a harmonic ringer, the clapper and arm are mechanically constructed to respond only to one specific frequency of the ringing voltage, and not to other frequencies. Again, a way to selectively ring one party on a party line.

I don't know the term "straight line", but it sounds like it refers to an ordinary everyday ringer.

Bill

[benhutcherson]

Here's my understanding:

Normal ringing voltage in the United States is a nice, pretty sinusoidal 20 HZ, 90 V AC. Your typical "A" type ringer, such as the venerable WE C4A used in the 500 set, etc., will operate on anything between 20 and 30 Hertz. A B type ringer, such as the buzzer or warbler type used in many newer telephones, will operate on a wider range of frequencies-16 to 60 hertz, as memory serves. Either of these would be a straight-line ringer.

A biased ringer will only ring when a small DC offset("bias"), somewhere in the neighborhood of 1-2 volts, is present on the ringing signal.

Finally, a harmonic ringer is tuned to respond to only one specific frequency. As memory serves, the frequencies used are 16.6 hz, 20 hz, 33.3 hz, 45 hz., and 66 hertz.

Of course, all of this would be used to give selective ringing on a party line. By using biased tip-to-ground and tip-to-ring ringer wiring, combined with biased(+ or - offset) and harmonic ring(5 different frequencies), it becomes possible to have as many as 20 parties on one line with selective ringing.

By the was, as far as I know, the Bell System only used biased ringing and tip-to-ground/tip-to-ring-I'm not aware of them ever using harmonic ringing. Thus, if more than four parties were to be on a Bell System line, only semi-selective ringing was possible.

[TIPandRING]

So far I agree 

Per Automatic Electric;

Straight Line is a regular ringer.
90 volts AC or so at 20-30 hz thru a .47 uF cap will make a nice ring.

Harmonic. The dc blocking capacitor was carefully chosen with the bells to only respond to the correct hz range. (Care taken to make it a resonant circuit) Special frequencies were chosen so they were not harmonics of each other. This and connecting the bells from either TIP to ground or RING to ground allowed for many phones on a party line circuit.

I've got a whole book on the ways of AE if anyone wants specifics on frequencies, wiring schemes etc.