Re: Caller ID (was Re: Enough!)

[Chris Benson]

On Wed, May 16, 2001 at 11:15:52AM +0100, 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...

My faux-ISDN (HomeHighway) tells me things like:

* tei 115 calling +44 /8452120667, Great Britain with +44 1912/39, Tyneside  RING 
(Data)
tei 115 calling +44 /8452120667, Great Britain with +44 1912/39, Tyneside  CONNECT 
(Data)
tei 115 calling +44 /8452120667, Great Britain with +44 1912/39, Tyneside  1.CI 
0.120 DM (now 
tei 115 calling +44 /8452120667, Great Britain with +44 1912/39, Tyneside  NEXT CI 
AFTER 00:1 Euro 2, Wochenende (Samstag))
tei 115 calling +44 /8452120667, Great Britain with +44 1912/39, Tyneside  0.CI 
0.000 DM (aft   )
tei 115 calling +44 /8452120667, Great Britain with +44 1912/39, Tyneside  NEXT CI 
AFTER Euro 2, Wochenende (Samstag))
tei 115 calling +44 /8452120667, Great Britain with +44 1912/39, Tyneside  HINT: 
Overall cheapest 01011:o.tel.o CbC 0.000 DM (saving 0.000 DM)
tei 115 calling +44 /8452120667, Great Britain with +44 1912/39, Tyneside  HINT: 
LCR:OK   

(The driver does numeric->German translations for free).
If anyone rings my number I vaguely remember it telling me the German
for "number withheld", but I don't answer anymore so no-one rings.

Real ISDN can use the D channel to do neat things like re-direct calls ...
without tying up any of your channels, your PBX just tells the exchange 
to route the call elsewhere after you've looked at the details.  

Some people on news:uk.telecom had various schemes for
- redirecting incoming junk faxes to other premium-rate fax numbers 
- diverting CLID withheld to a TAM "This number does not accept anonymous
calls, please redial.  You *have* been charged for this call. "
- diverting CLID unavailable to a (different) TAM "Please leave a message".

-- 
Chris Benson

Re: Caller ID (was Re: Enough!)

[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.

Re: Caller ID (was Re: Enough!)

[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!)

[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!)

[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!)

[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!)

[Robin Szemeti]

On Wed, 16 May 2001, Jonathan Peterson wrote:
> 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.

umm maybe in the US .. 

In the UK the CLDN (calling line dialled number) is stripped at the
terminating exchange and replaced with a 'reason for abscence of dialled
number' code ('O' for unavailable, 'P' for withheld .. theres logic in
there somewhere ;)

if it really did send it on it would just be too easy to make a box to
display numbers whether they were withheld or not. Obviously the telcos
still have access to the routing information internally, for call tracing
and such, but its not passed on to the customer. 

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.

-- 
Robin Szemeti

Redpoint Consulting Limited
Real Solutions For A Virtual World

Re: Caller ID (was Re: Enough!)

[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.

BT do offer this service if you are on an AXE10/System X switch



It's called "Anonymous Call Rejection" 

It's even available on UXD5 which are very old rural exachanges.



-- 
1024/D9C69DF9 steve mynott [EMAIL PROTECTED]

reality is that which, when you stop believing in it, doesn't go away.
-- philip k. dick

Re: Caller ID (was Re: Enough!)

[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:-



-- 
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

Caller ID (was Re: Enough!)

[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]