Well, I was able to discover 2 chips that seem to be good for decoding the
caller ID stuff.....
Even found the odd FSK Modem chip but were not proper audio freqs for CID.
If anyone comes across some PIC source code on how to generate the CallerID
transmission please, by all means forward it to myself. I can figure out
the actual data bits to send, but generating a carrier frequency and
modulating it at the correct frequencies is beyond me. I'm more or less just
a "digital" type, analog scares me :)
PS: I suppose I could just do some fancy switching to send the data portion
through to the remote phones......
I have found, in my great stack of electronics magazines, the article from
the August 1996 Popular Electronics, about a Caller ID - PC interface, using
a PIC and the Motorola CallerID chip. Anyone who wants it can mail me
off-list - I've scanned it in.
> I have found, in my great stack of electronics magazines, the article from
> the August 1996 Popular Electronics, about a Caller ID - PC interface, using
> a PIC and the Motorola CallerID chip. Anyone who wants it can mail me
> off-list - I've scanned it in.
> -Randy Glenn
> E-Mail: .....PICxpertKILLspam@email@example.com
> Web: http://i.am/PICxpert
> Currently wondering why I can't get in to Safe Mode - where's a Mac when you
> need it?
John, I've done plenty of telephony, CID, blah blah blah and I have to
tell you, if it was me I'd leave the phones DC connected to the telco all
the time, except when I specifically wanted to take over a line. I'd use a
one of those part-68 or better yet BATB approved line siezure detect
relays in series with each phone to know when it came offhook. I would
connect only passive components to the phone line: movs, relays,
flame-proof resistors. FLASH would relay the phone over to 'command' mode,
i.e. 6V with DTMF detect (I would remember that I have line sieze detect
per line, I can tell who flashed). So commands would be FLASH 1, FLASH 2,
etc. I would also remember to have a command like FLASH 9 that caused a
'real' flash on the telco.
Why? First, if everything on the line is passive, I would be able to get a
waiver on part 68, so no 6 month repeat inspection, Second, IIRC Caller ID
is licensed by Nortel. Third, there's quite a variety of onhook services
besides Caller ID: VMWI, ADSI, stutter dial tone, ring cadences, CID call
waiting, etc. It is unlikely that I could accurately model the entire
phone system, and certainly couldn't predict it: I wouldn't want customers
to complain when the emulation didn't support some new magic service.
Also if it was me, I totally ignore pulse dial phones. But on the other
hand it isn't me :)
> Date: Thu, 3 Feb 2000 18:20:13 -0500
> From: John Mullan <jmullanKILLspamHOME.COM>
> Reply-To: pic microcontroller discussion list <.....PICLISTKILLspam.....MITVMA.MIT.EDU>
> To: EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU
> Subject: More about PIC and CallerID
> Well, I was able to discover 2 chips that seem to be good for decoding the
> caller ID stuff.....
> MC14LC5447 Motorola
> MT88E43BE Mitel
> Even found the odd FSK Modem chip but were not proper audio freqs for CID.
> If anyone comes across some PIC source code on how to generate the CallerID
> transmission please, by all means forward it to myself. I can figure out
> the actual data bits to send, but generating a carrier frequency and
> modulating it at the correct frequencies is beyond me. I'm more or less just
> a "digital" type, analog scares me :)
> John Mullan
> PS: I suppose I could just do some fancy switching to send the data portion
> through to the remote phones......
Sounds like a good idea. I really want to add the ability to call each
extension phone using seperate voice paths. Your idea would work if I
utilized a few extra relays. I could just monitor the line and switch as
necessary, either by listening for DTMF or FLASH. Come to think of it, I
would listen for DTMF so that FLASH could remain it's usual function.
I've already invested in the Mitel hybrids and don't want to waste them.
This really isn't a commercial venture yet. It is something for me to work
on between projects. I can handle everything I need to, just not passing
the CNID data to capable sets. I wouldn't even care but the wife (already
distraught over the fact that I am concocting another device, hehehe) loves
her CallerID so I need to plan it into my circuit.
My alternative to date is to run 4 wire to each jack. Bypass any CNID
processing, switch the current ringing line to the spare pair and just use
dedicated boxes. But then that wastes the phones I have already.
Oh well, the standard is plain enough, just need to generate the carrier and
properly formated data packet and modulate. Seems simple but I'm a digital
guy and analog is not my strong suit.