judice@kyoa.enet.dec.com (Lou Judice 15-Aug-1989 0916) (08/16/89)
While moving offices recently, we noticed the following odd label on the bottom of AT&T straight sets (normal single line phones): WARNING USE FOR BUSINESS SYSTEMS ONLY OR YOU RISK AN ELECTRICAL SHORT CIRCUIT. The phones are on a Dimension PBX. I'm sure I've put consumer phone stuff on a Dimension without frying it, so I'm curious about this. (Note, I could understand if this was a digital phone or a MET-set type phone). /ljj
aem@ibiza.cs.miami.edu (a.e.mossberg) (08/16/89)
judice@kyoa.enet.dec.com (Lou Judice 15-Aug-1989 0916) writes: >While moving offices recently, we noticed the following odd label on the >bottom of AT&T straight sets (normal single line phones): > WARNING > USE FOR BUSINESS SYSTEMS ONLY OR YOU > RISK AN ELECTRICAL SHORT CIRCUIT. When we got new phones (at a former company) the first thing I did was borrow someone elses's phone (-:) and plug it into an outside line in my office. Worked fine. My guess was that the notice was to discourage people from taking home these nice phones. Though, it could be that some of the line-powered features on these phones have no protection--and count on being on fairly well protected circuits. aem a.e.mossberg - aem@mthvax.cs.miami.edu/aem@umiami.BITNET - Pahayokee Bioregion Chances that a homeless American holds a full- or part-time jobs: 1 in 5 - Harper's Index 2/89
covert@covert.enet.dec.com (John R. Covert 22-Aug-1989 1357) (08/23/89)
>While moving offices recently, we noticed the following odd label on the >bottom of AT&T straight sets (normal single line phones): > > WARNING > > USE FOR BUSINESS SYSTEMS ONLY OR YOU > RISK AN ELECTRICAL SHORT CIRCUIT. They're not _quite_ normal single line phones. If you look at the number on the bottom, you'll see that it is 2500 DM rather than 2500 D. The "M" means that the yellow-black pair is connected to a switch inside the phone which closes when you pick up the phone. This would be connected to the "A" and "A1" leads of a key system to make the lights on a key telephone light and to make your phone interact properly with your secretary's hold circuit, if necessary. The reason for the warning is that in older residential installations, Y-BK carries power for dial lights. And, to make matters worse, one series of transformers used to power those lights could create a fire hazard when shorted. /john
sklar@ihlpl.att.com (Robert S Sklar) (08/24/89)
In article <telecom-v09i0300m08@vector.dallas.tx.us>, judice@kyoa.enet.dec.com (Lou Judice 15-Aug-1989 0916) writes: > While moving offices recently, we noticed the following odd label on the > bottom of AT&T straight sets (normal single line phones): > > WARNING > > USE FOR BUSINESS SYSTEMS ONLY OR YOU > RISK AN ELECTRICAL SHORT CIRCUIT. > > > The phones are on a Dimension PBX. I'm sure I've put consumer phone stuff > on a Dimension without frying it, so I'm curious about this. (Note, I > could understand if this was a digital phone or a MET-set type phone). > > /ljj The reason for the warning is probably for the sub-case where someone attempts to plug this phone into an RJ14 *TWO-LINE* jack. A business analog phone, probably a 2500M, is wired differently than its residential equivalent, a 2500D. The business phone uses the yellow-black pair for A-A1 supervision (the hook-switch short-circuits the pair so that the PBX|KSU knows that the line was picked-up and can light the appropriate lights on multi-line phones). On a 2500D this hookswitch pole is used for other purposes. Therefore, if you install a 2500M or equivalent in a two-line residential installation without opening the yellow-black connection to the hookswitch, you will short-out the second line every time you pick up this phone. Robert Sklar (Lachman Associates, Inc @) AT&T Bell Laboratories Naperville, IL
dupuy@cs.columbia.edu (Alexander Dupuy) (08/26/89)
Does anyone know what the meaning of the letter codes after the model # on phones is? I have an old 500DM(?) black rotary standard which I like because it works even when the AC power is out, and because it rings loud enough to hear it across the apartment. Is there any possibility it will short out my second line when I hook that up? @alex
macy@hal.uucp (08/26/89)
In article <telecom-v09i0300m08@vector.dallas.tx.us> judice@kyoa.enet.dec.com (Lou Judice 15-Aug-1989 0916) writes: >X-TELECOM-Digest: volume 9, issue 300, message 8 of 8 >While moving offices recently, we noticed the following odd label on the >bottom of AT&T straight sets (normal single line phones): > > WARNING > > USE FOR BUSINESS SYSTEMS ONLY OR YOU > RISK AN ELECTRICAL SHORT CIRCUIT. Generally speaking, this indicates the sets are modified for use behind 1A2 key telephone equipment. This older style electromechanical key equipment tequired a single line set to put out a dry contact closure when off hook, on the yellow+black base cord wires. These same wires were used in residential applications to provide dial light power for Trimline sets, from a 2012A transformer. Unless the 500/2500 sets were field modified, the suffix on the designation was different form the usual 500D (Its been too long, I can't remember all the old Western Electric numbers!) I've got my old Key Syetems Manual around her somewhere.... Plug in a A-lead control set in a residence and during the next long phone call using that set, the subscriber would notice a distict smell of charred copper+enamel insulation. Rumor had it that more than one residence burned to the ground due to shorted dial light transformers ! Macy Hallock fmsystm!macy@NCoast.ORG F M Systems, Inc. hal!ncoast!fmsystm!macy Medina, OH 44256 Voice: 216-723-3000 X251 Disclaimer: My advice is worth what you paid for it.