Wayne Chirnside wrote in a message to Roy J. Tellason:

> certain value. The teleprotector is a diode bridge and SCR
> arrangement that senses the phone line voltage, on hook, off hook,
> and if it detectect low voltage off hook conditions it effectively
> opens the phone line downleg of the protector. I originally bought it

WC> Mines over seven years old years but when I bought it it was 9.95.
WC> I was going to make the darn thing it was so simple but by the time
WC> you bought parts, case, modular plugs, modular plug crimping tool...

RJT> Easy enough to take a spare cable,  cut it in half,  and wire it
RJT> between a pair of jacks on the wall...

WC> Actually as I was responding to Charles it occured to me there was
WC> room enough in the modular jack for the device so that jack could
WC> be computer dedicated and anything else hung off another jack
WC> downleg of the device on other jacks. Pretty much as you say above
WC> but without the need for the wire and the thing would be totally
WC> hidden.

Sounds good.  And just as easy as the other way.  I guess it depends on
what sort of stuff you have handy...

WC> These things prevent eavesdropping as well. IIRC the whole thing is 
WC> just a couple resistors, a low current and thus small SCR and some 
WC> steering diodes of the signal type variety rather than bulkier 
WC> current rectifiers.

I sure have enough of those on hand!  Except maybe for SCRs.

RJT> I remember a circuit that was *real* simple,  just a couple of
RJT> transistors and a small number of discrete parts.  For starters,  you
RJT> could have it drive an LED and it'd serve as a "phone-in-use" 
RJT> indicator.  Or have it drive a relay, and it'd control a tape 
RJT> recorder.  In the case of what you're talking here,  it just 
RJT> disconnects the stuff upline from there.

WC> The phone in use thing is cool but you can't hang much off of PH.
WC> Co. lines power without it messing things up so added complication
WC> of independent power. The teleprotector is pretty much a passive 
WC> device using steering diodes.

Yeah,  the gizmo I'm thinking of did need some batteries.  But a couple of
AAA cells would last a *real* long time.  Particularly since I had the
circuit driving one of those LM3909 LED flasher chips,  which I'd also
gotten at around that time to play with.

RJT> I had done some wiring at one point for the phone setup when we had
RJT> "the shop",  and would occasionally do modeming in there.  To 
RJT> prevent me from getting interrupted,  the phones that were tied to 
RJT> that (second) line were fed the line from the "phone" jack in the 
RJT> back of the modem -- when it was in use there was no connection 
RJT> there.

WC> You know I've never checked to see if mine cuts off the telephone
WC> leg? 

Some do,  some don't.

WC> Got the thing wired to keep me from connecting the H.P. if the
WC> NEC is active. Not really neccessary in my current situation but
WC> the thing had been just lying in the box and I noted that when the
WC> NEC dialed out the H.P. woke up from standby mode.

Interesting,  I wonder if it's set to wake on ring?  And if perhaps it's
picking up on some line transient as being a ring?

WC> I did use to need the device when Cynthia would pick up the phone
WC> scrambling my downloads some years ago.

Whenever you have anybody else in the house it'd be handy,  because people
don't think it's important to check...

WC> Need to get a good day going soon so I can cut a piece of plywood
WC> to modify the stereo stand to take the computer thus placing both
WC> machines at my disposal within reach.

WC> I may be disabled but soon I'll have some impressive multimedia and
WC> computer setups. Currently one cheap stereo on the VCR and I've
WC> another I can slap on the bottom tray of this cart for the
WC> computerf leaving room for the printer on the second tray.

Well,  we all have stuff we gotta deal with...  :-)

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