Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!think.com!sdd.hp.com!zaphod.mps.ohio-state.edu!casbah.acns.nwu.edu!nucsrl!telecom-request From: Barton.Bruce@camb.com (Barton F. Bruce) Newsgroups: comp.dcom.telecom Subject: Re: How do You Hook up a Phone For a Play? Message-ID: Date: 20 Feb 91 09:27:35 GMT Sender: news@casbah.acns.nwu.edu Organization: Cambridge Computer Associates, Inc. Lines: 23 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 138, Message 7 of 8 Originator: telecom@delta.eecs.nwu.edu Certainly running a stage phone off 110 is a dangerous idea, but the main problem is that it may well NOT work. The standard 'straight line' ringer will work over the full ringing range phones are rung with - ~16 - 66 hz, BUT the weird frequencies are normally done with tuned ringers designed to ONLY ring at that frequency. The straight line ringers normally are used on 20hz from the CO and 30 hz in a Key system. At 60hz you may need up near 160 volts to get it ringing. Normally ringing is SUPERIMPOSED on DC to provide for ring tripping, but the DC is blocked by the .5 mfd cap, so is irrelevant for clanging the bell. N.B. that the original post was by an AT&T Bell Labs type. Early on I mailed to him suggesting simply grabbing (at work presumably there should be LOTS somewhere) a small plug in key system ringing generator like the WE 118A. It is the size of a FAT modem transformer, but has a short cord + plug rather than built in prongs. I suggested wiring the phone directly to it, and plugging it in to the stage light panel so some existing switch would ring the bell. These supplies are 30hz and are very current linited. For someone not working for Bell Labs, the local phone company is apt to help with school plays - free.