Post by thread:[EE:] Phone ring based on CID info. [was: standard

On Thu, Jul 29, 2004 at 07:18:59PM -0700, Harold Hallikainen wrote: > Thread drift here... but anyone know of an external EIA232 data/fax/voice > modem that includes "snoop mode?" I'd like something that listens to the > line without going off hook. It would listen for fax CNG tones or for the > data originate tone (some modems send something similar to CNG on data > calls so they can be identified). I'd like to hang it on a linux machine > at home and tie it across our dial up phone line. Incoming faxes would be > converted to email. Incoming modem calls would be allowed to log in and > set up a ppp connection. Other calls would be ignored and be picked up by > an answering machine or a human. So, any suggestions for modems with snoop > mode? Sounds like you have a chicken and egg problem: 1) "listens to the line without going off hook" 2) "listen for fax CNG tones etc." You don't get any tones (other than CID) until the phone is picked up. So I can't see how to get both behaviors at the same time. Something I'd like to see along a similar vein is a CID scanner, which is doable without going off hook. However I want a twist. Basic behavior: 1) Suppress first ring. 2) Get/lookup CID. If valid pass successive rings through. Otherwise suppress successive rings or route to answering machine. Now for the trick: 3) Facilitate CID info to flow through to the phones too. I think I have the same catch 22. In the US CID is detected after the first ring. If you suppress the ring, I don't think the phone will collect the CID info. BAJ -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

You may be able to get away with just passing a couple of cycles of ring to the phone. Most phone firmware isn't that smart and probably starts listening for CID immediately after seeing the ring signal stop. It's easy enough to test with two phones. Call your line and don't connect line until the last part of the 2 second ring cycle. You could even use a monostable and relay to test how short a ring your phone needs to start looking for CID. R Byron A Jeff wrote: {Quote hidden}> On Thu, Jul 29, 2004 at 07:18:59PM -0700, Harold Hallikainen wrote: > >>Thread drift here... but anyone know of an external EIA232 data/fax/voice >>modem that includes "snoop mode?" I'd like something that listens to the >>line without going off hook. It would listen for fax CNG tones or for the >>data originate tone (some modems send something similar to CNG on data >>calls so they can be identified). I'd like to hang it on a linux machine >>at home and tie it across our dial up phone line. Incoming faxes would be >>converted to email. Incoming modem calls would be allowed to log in and >>set up a ppp connection. Other calls would be ignored and be picked up by >>an answering machine or a human. So, any suggestions for modems with snoop >>mode? > > > Sounds like you have a chicken and egg problem: > > 1) "listens to the line without going off hook" > 2) "listen for fax CNG tones etc." > > You don't get any tones (other than CID) until the phone is picked up. So > I can't see how to get both behaviors at the same time. > > Something I'd like to see along a similar vein is a CID scanner, which is > doable without going off hook. However I want a twist. Basic behavior: > > 1) Suppress first ring. > 2) Get/lookup CID. If valid pass successive rings through. Otherwise suppress > successive rings or route to answering machine. > > Now for the trick: > > 3) Facilitate CID info to flow through to the phones too. > > I think I have the same catch 22. In the US CID is detected after the first > ring. If you suppress the ring, I don't think the phone will collect the CID > info. > > BAJ > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 12:54 AM 7/30/2004, Robert Rolf wrote: >You may be able to get away with just passing a couple >of cycles of ring to the phone. Most phone firmware >isn't that smart and probably starts listening >for CID immediately after seeing the ring signal stop. AFAIK, CID is sent after the first ring. Also, the audio path is present before the phone is answered. Several devices out there depend on this. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

> > Something I'd like to see along a similar vein is a CID scanner, which is > doable without going off hook. However I want a twist. Basic behavior: > > 1) Suppress first ring. > 2) Get/lookup CID. If valid pass successive rings through. Otherwise > suppress > successive rings or route to answering machine. > > Now for the trick: > > 3) Facilitate CID info to flow through to the phones too. > > I think I have the same catch 22. In the US CID is detected after the > first > ring. If you suppress the ring, I don't think the phone will collect the > CID > info. Is ringing actually required to activate caller ID? It seems like the caller ID unit could just continuously listen for CID data. On the ring suppression, how about a capacitor in series with the line so low frequency ringing does not get through, but high frequency CID data does get through. Once the CID determines this is someone you want to talk to, short out the capacitor and let the phone ring on the next ring. Harold -- FCC Rules Online at http://www.hallikainen.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

On Fri, Jul 30, 2004 at 07:31:45AM -0700, Harold Hallikainen wrote: {Quote hidden}> > > > Something I'd like to see along a similar vein is a CID scanner, which is > > doable without going off hook. However I want a twist. Basic behavior: > > > > 1) Suppress first ring. > > 2) Get/lookup CID. If valid pass successive rings through. Otherwise > > suppress > > successive rings or route to answering machine. > > > > Now for the trick: > > > > 3) Facilitate CID info to flow through to the phones too. > > > > I think I have the same catch 22. In the US CID is detected after the > > first > > ring. If you suppress the ring, I don't think the phone will collect the > > CID > > info. > > > Is ringing actually required to activate caller ID? It seems like the > caller ID unit could just continuously listen for CID data. Not sure. The US spec is clear that CID info is only presented between the first and second rings (excluding advanced call waiting). > On the ring > suppression, how about a capacitor in series with the line so low > frequency ringing does not get through, but high frequency CID data does That's one idea. One way to easily suppress ringing is to use a bridge rectifier between tip and ring. I've tested this and it works. However CID didn't get through. > get through. Once the CID determines this is someone you want to talk to, > short out the capacitor and let the phone ring on the next ring. Some combination of the two will hopefully work. All that's needed then is a Rat-Ring type PIC circuit to sample the CID, lookup one a white/black list, and determine if the phones get to ring or if the caller is shunted to a prerecorded message. BAJ -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

Snooping with a modem may not work as you think. The V92 etc modems do some handshaking and code/compression table sharing that is hard to follow by a third party. What you can do relatively easily is to use an external fax/modem/voice dispatcher box [*] (buy locally) and eventually tap into it or hack it to connect to your linux machine. Building such a box is not hard but it takes a lot of testing to find most bugs. Peter [*] it's a box that connects to the phone line and has connectors for phone, fax and modem. You can then program which one receives calls, between what hours, which one dials out etc etc. There are dozens of different models. Recently these are replaced by mini-pbx units which do all these can do, but better. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics