tep@ucsd.edu (Tom Perrine) (03/03/91)
In article <telecom11.167.1@eecs.nwu.edu> bruce@camb.com (Barton F. Bruce) writes: X-Telecom-Digest: Volume 11, Issue 167, Message 1 of 11 > The traditional ringer IS sensitive to the polarity of pulses! Aside > from adjusting the bias spring, the 'proper' cure for BELL-TAP > (tinkeling as a rotary extension or other party dials or even just > goes on/off hook) is to have the phone's two wires connected properly > to TIP and RING. > There may be a bias spring that can be hooked to a stiffer notch that > will help. I am asking this question because the original article meseems to be talking about TT phones and their ringers. My father-in-law has a real Bell rotary phone that was installed in 1960. It has, of course never been serviced. In the last ten years or so, it has developed what sounds like bell-tap; when you dial, the ringer makes one "ding" for every pulse in the number. When an extension was added (by TPC), we discovered that dialing the extension (a cordless, set to pulse-dial) also causes the original phone to "ding". Is this "bell-tap"? Is it a matter of reversing the polarity on the pair, or is it due to wear in the electro-mechanical ringer? After thirty years, I would assume that it could be a *little* out of adjustment :-). Inquiring minds want to know! Tom Perrine (tep) |Internet: tep@tots.Logicon.COM Logicon - T&TSD | UUCP: sun!suntan!tots!tep P.O. Box 85158 |GENIE: T.PERRINE San Diego CA 92138 |Voice: +1 619 455 1330 | FAX: +1 619 552 0729
Barton.Bruce@camb.com (Barton F. Bruce) (03/04/91)
In article <telecom11.175.11@eecs.nwu.edu>, tots!tots.Logicon.COM! tep@ucsd.edu (Tom Perrine) writes: > so, it has developed what sounds like bell-tap; when you dial, the > ringer makes one "ding" for every pulse in the number. When an > extension was added (by TPC), we discovered that dialing the extension > (a cordless, set to pulse-dial) also causes the original phone to > "ding". > Is this "bell-tap"? Yes. > Is it a matter of reversing the polarity on the pair, The biased ringers are most immune to tap when connected properly across the line. (Keeping it simple...) the green cord wire should go to the line wire that is + (on any el-cheapo vom) in relation to the other wire. > or is it due to wear in the electro-mechanical ringer? After > thirty years, I would assume that it could be a *little* out of > adjustment :-). Not much wear likely, but the little spring hooks in different notches. If set way up high, the bell may not ring if the loop is very long. If set too weak, the bell will tap especially on short loops (where there is plenty of power to ring with the spring set stiff). BTW, I assume that TT/DP extension has been tried in TT mode even if you don't pay for the service.
dave@westmark.westmark.com (Dave Levenson) (03/09/91)
In article <telecom11.175.11@eecs.nwu.edu>, tots!tots.Logicon.COM!tep@ ucsd.edu (Tom Perrine) writes: > Is this "bell-tap"? Is it a matter of reversing the polarity on the > pair, or is it due to wear in the electro-mechanical ringer? After > thirty years, I would assume that it could be a *little* out of > adjustment :-). The most likely culprit here is the blocking capacitor. This is probably a 1 or 2 mFd capacitor mounted inside the 'network' (the potted module in the right rear corner of the instrument with a bunch of screw-terminals on top) and connected between terminals A and K. It is normally wired in series with the ringer, so that only the AC component of the signal passes through the ringer. It has probably become shorted, allowing the DC to bias the ringer. The dial pulses look like 48 volt DC pulses, and will tap the bell if the capacitor is shorted. If AT&T still owns the telephone, they should replace it. Dave Levenson Internet: dave@westmark.com Westmark, Inc. UUCP: {uunet | rutgers | att}!westmark!dave Warren, NJ, USA AT&T Mail: !westmark!dave Voice: 908 647 0900 Fax: 908 647 6857