Re: [OT] Electronics Circuit Help

[Kevin Hawkins <lists@xxxxxxxxxxxxxxxxx>]

Ignoring the electronics for a moment don't you really only have two
lines ? If you put the CID unit on the incoming line before the
distinctive ring units then an incoming call  will provide CID info
whichever number is being dialled, or are you also trying to determine
which number was called ? As you only have one serial port this isn't
going to be possible. Actually connecting it after one of those
'distinctive ring' dividers may cause them both to provide CID info
(which is sent with a line reversal) or may not provide CID at all - I
would be most surprised if it split the CID out as the first couple of
rings are lost whilst the unit determines the distinctive ring pattern.

I am not sure on the line isolation provided by the CD50 mod - is it an
optical isolator I wonder.  You may be able to combine the received data
by just popping on a couple of diodes, but as you are now back to only
two serial ports needed maybe that is the easiest way , and you would
get separate line identification.

Kevin

Martyn Wendon wrote:
> Hi,
>
> Can anybody with electronics expertise assist with a circuit design
for
> connecting multiple caller id boxes to a PC serial port?
>
> Background:
>
> I've got four phone lines (well actually 2, but they both have
distinctive
> ring secondary numbers, so I effectively have 4 sources) and I want to
get
> caller id information onto my xAP network.
>
> My options are:
>
> 1) Multiple Meteors (expensive)
> 2) One of the Meteor multi-line jobbies (even more expensive)
> 3) 4 PCI Modems with Caller-Id (Probably an IRQ nightmare, plus PCI
modems
> with BT caller-id seem to be rare)
> 4) Some sort of line card (brooktrout maybe, but probably expensive
> 5) Make something to do it
>
> So I'm going with option 5 :)
>
> So far I've got enough components / parts to follow the details at
> http://www.amarok.demon.co.uk/dl/cd50_mod/
and make 4 of them.  However that
> gives me an issue with needing 4 serial ports which I'd like to
overcome (I
> don't want to use a multi-serial card as from a software point of view
I'd
> rather have the data appear on one serial port).
>
> So I need a circuit of some kind that will take the output of 4 of the
> hacked caller id boxes and present it on one serial port.
>
> Me electronics knowledge is limited, although I can use a soldering
iron!
> Can somebody assist?
>
>
> Thanks for any pointers,
>
> Martyn
>
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