Caller ID (was Re: Enough!)

2001-05-16 Thread Jonathan Peterson

At 21:08 15/05/01 +0100, you wrote:

They already offer it.
You can bar up to ten numbers (IIRC). I don't know how it deals
with withheld numbers. Never checked.

I'm sure I remember reading somewhere that you always send your CID when 
you make a phone call. If you choose to withhold the ID, it still gets 
sent, it just gets sent with a 'do not disclose' flag set, which all (BT 
approved) phones and services (like 1471) must honour. Therefore it should 
be easy for BT themselves to offer something that can bar CID witheld 
calls.

But this might be wrong, or might just be how the US system works or 
something.


-- 
Jonathan Peterson
Technical Manager, Unified Ltd, 020 7383 6092
[EMAIL PROTECTED]




Re: Caller ID (was Re: Enough!)

2001-05-16 Thread Steve Mynott

Jonathan Peterson [EMAIL PROTECTED] writes:

 I'm sure I remember reading somewhere that you always send your CID when 
 you make a phone call. If you choose to withhold the ID, it still gets 
 sent, it just gets sent with a 'do not disclose' flag set, which all (BT 
 approved) phones and services (like 1471) must honour. Therefore it should 
 be easy for BT themselves to offer something that can bar CID witheld 
 calls.
 
 But this might be wrong, or might just be how the US system works or 
 something.

This is basically right but some ways of making a call don't send any
CLI at all and the US and UK systems are different.

The BT specs are online:-

http://www1.btwebworld.com/sinet/227v3p1.pdf

-- 
1024/D9C69DF9 steve mynott [EMAIL PROTECTED]
the difference between a moral man and a man of honor is that the latter
regrets a discreditable act, even when it has worked and he has not
been caught.  -- henry l. mencken



Re: Caller ID (was Re: Enough!)

2001-05-16 Thread Dominic Mitchell

On Wed, May 16, 2001 at 10:59:07AM +0100, Robin Szemeti wrote:
 I do keep intending to do something cute with my ISDN adapter and log the
 stuff coming out of the D channel and see whats in there ... but time has
 prevented it etc.

I'd be interested to hear how you get on... I was under the impression
that the D channel was an always on 16k-thing.  It'd be interesting to
see what gets sent down there normally...

-Dom



Re: Caller ID (was Re: Enough!)

2001-05-16 Thread Matthew Byng-Maddick

On Wed, 16 May 2001, Dominic Mitchell wrote:
 On Wed, May 16, 2001 at 10:59:07AM +0100, Robin Szemeti wrote:
  I do keep intending to do something cute with my ISDN adapter and log the
  stuff coming out of the D channel and see whats in there ... but time has
  prevented it etc.
 I'd be interested to hear how you get on... I was under the impression
 that the D channel was an always on 16k-thing.  It'd be interesting to
 see what gets sent down there normally...

CLI / Destination number that kind of thing. Signalling information
basically.

MBM

-- 
Matthew Byng-Maddick  [EMAIL PROTECTED] +44 20  8980 5714  (Home)
http://colondot.net/ +44 7956 613942  (Mobile)
In California they don't  throw their  garbage away  --  they make it into
television shows. -- Woody Allen, Annie Hall




Re: Caller ID (was Re: Enough!)

2001-05-16 Thread Robin Szemeti

On Wed, 16 May 2001, Dominic Mitchell wrote:
 On Wed, May 16, 2001 at 10:59:07AM +0100, Robin Szemeti wrote:
  I do keep intending to do something cute with my ISDN adapter and log the
  stuff coming out of the D channel and see whats in there ... but time has
  prevented it etc.
 
 I'd be interested to hear how you get on... I was under the impression
 that the D channel was an always on 16k-thing.  It'd be interesting to
 see what gets sent down there normally...

ummm it might be 9k6 but yes, its always on. My card will do either two B
(64k) channels or a B and D channel ... 

most of what gets sent down there is CLID, charge info, etc .. I think
they strip a load of it off if you only pay for home highway .. and allow
it through if you pay for business highway... ie they actually go to some
trouble to provide a worse service .. fules.

-- 
Robin Szemeti

Redpoint Consulting Limited
Real Solutions For A Virtual World



Re: Caller ID (was Re: Enough!)

2001-05-16 Thread Steve Mynott

Matthew Byng-Maddick [EMAIL PROTECTED] writes:

 On Wed, 16 May 2001, Dominic Mitchell wrote:
  On Wed, May 16, 2001 at 10:59:07AM +0100, Robin Szemeti wrote:
   I do keep intending to do something cute with my ISDN adapter and log the
   stuff coming out of the D channel and see whats in there ... but time has
   prevented it etc.
  I'd be interested to hear how you get on... I was under the impression
  that the D channel was an always on 16k-thing.  It'd be interesting to
  see what gets sent down there normally...
 
 CLI / Destination number that kind of thing. Signalling information
 basically.

I have heard of people using the D channel signalling to communicate
for free.

-- 
1024/D9C69DF9 steve mynott [EMAIL PROTECTED]

liberty is always dangerous, but it is the safest thing we have.
-- harry emerson fosdick



Re: Caller ID (was Re: Enough!)

2001-05-16 Thread Philip Newton

Steve Mynott wrote:
 I have heard of people using the D channel signalling to communicate
 for free.

I've also heard of phone companies cursing such users and trying to ban
programs that support that.

At least in Germany, there was a program (or several?) that took advantage
of the fact that when you initiate a connection, you can also transfer a
small data packet. So they would initiate a connection and include a small
data packet, then immediately tear down the connection before it was
answered, and initiate another connection with the next few bytes. All this
stuff was free (since no connection was established completely), but
apparently a lot of load on the switching network.

However, German Telecom used to have a service (don't know whether they
still do) whereby you could have an always-on connection using the D channel
with a type of Datex-P-over-ISDN (a packet-switched(?) network in Germany
where you pay by the packet rather than by the minute, and where no
permanent connections are established: a bit like UDP). So you could have
your email delivered to you, or stock ticks, or other stuff that didn't need
high bandwidth.

Cheers,
Philip
-- 
Philip Newton [EMAIL PROTECTED]
All opinions are my own, not my employer's.
If you're not part of the solution, you're part of the precipitate.