Re: ring killer

does anyone have a design for a cct that shorts ring

> current and is switched by the pc? > this would be _very_ handy when combined with caller > id software as the phone will not ring until the software > has decided the caller is not blacklisted.

You don't want to "short" the ring current, you want to open the circuit and not let the ring current through to any ringers until the CID has approved the number.

Relay should remain closed at other times to preserve normal functionality of phone system.

Reply to
Richard Crowley
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In article , snipped-for-privacy@hotmail.com mentioned...

If you short the ringer current, the phone line will go off hook, and the ringing will stop. Then you have to fake the ringing sound to the far end so they think that the line is still ringing.

So why don't you just get a box that does this for you? You can buy a card to go into the PC from such companies as Dialogic.

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Reply to
Watson A.Name - 'Watt Sun'

Jim, I know this sounds like a dumb question which it probably is, but if you don't want the ring, why not just turn off the ringer?

Harry C.

Reply to
Harry Conover

How does a modem do it? Lots of modems have CID in them. And since they hook up to serial ports, I can't think of a cheaper way to do it. Get an external 14.4 modem, hook it up to a PIC/AVR/mainframe (don't want to start a flame war), send the AT codes to enable CID, and have the PIC enable a relay at the point where your phone line enters the house. Of course, the modem needs to be between the line entry and the relay... Supra made a great external 14.4 modem with CID. 5$ on eBay??? I can picture a blob of circuitry hanging off the 14.4's DB-25 and powered by the wall wart.

Reply to
A E

Indeed. I have a little $50 box called a ComShare 450 that does this for me, while also routing fax calls to the fax machine, data calls to the computer, and voice calls to my answering machine and telephones. If I'm on-line with my computer, anyone that picks up a phone gets only a series of warning beeps indicating that the line is already in use.

I've had it for about 10 years, and it has proven itself to be among the best $50 investments I've ever made.

Harry C.

Reply to
Harry Conover

The modem needs to support CID/Bell 202.

CID (in the USA, I know parts of Europe use DTMF) uses the Bell 202 standard, so if you can find an AFSK ,modualtor, and re-create the bit stream, you can replicate it.

Reply to
Gary Tait

Hi, I was once asked to design a similar circuit using a caller ID chip. it worked fine, so I added a digitised voice chip to answer the phone witout it ringing and send a message to say that the owner did not want unidentified callers. The point being that answering in this way did not disturb the owner but the caller lost money.

switched

Reply to
Keith Buck
-

->does anyone have a design for a cct that shorts ring current and is switched

->by the pc?

->this would be _very_ handy when combined with caller id software as the

->phone will not ring until the software has decided the caller is not

->blacklisted.

-

-I posted a question about a Radio Device awhile back... it simply had

-a full-wave rectifier between TELCO and the Phone to prevent ringing.

I tested it. Works like a champ. However that isn't the hard problem as the OP has pointed out.

-

-This could be implemented with a relay instead of a slide switch to

-allow PC control.

-

-The Caller-ID mechanism *must* be on the TELCO side... I tried it

-after and the CID data can not be seen.

Exactly the problem. All the phones in the house have CID devices and you want to pass the CID info to them. However you don't want the phone to ring until the call has been whitelisted. I wonder if phones will accept CIS info without the first ring? Then maybe the CID info can be passed though while the ring is filtered.

Not exactly an easy problem.

BAJ

Reply to
Byron A Jeff

Why? Block ALL ringing (including the first one if necessary for initiating CID detection.) Then enable ringing if from a validated CID.

Already established that the circuit must be directly on the line BEFORE any interruption method for the house phones. So it has access to all the ring cycles including the first one.

Reply to
Richard Crowley

Ahhh. Didn't realize that you wanted the phones also to display CID. Presumed (wrongly) that only the device needs to know CID to make the decision whether to pass the incoming call.

Reply to
Richard Crowley

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