ISDN Modem

[Daniel Smith]

On Thu, Jan 02, 2003 at 07:13:34PM +1100 or thereabouts, Grant Holliday wrote:
> Hi all,
> 
> I'm running the internet caf? out at camp Cottermouth for the Scouts
> Venture 2003. See the (quite poor) website www.venture2003.com
> 
> After some googling I've learnt a bit about ISDN. To make DOV (Data Over
> Voice) calls which are untimed, you need an additional modem to the NT1
> Plus II TA that Telstra have provided. Is this correct?

Correct, but you would normally require this anyway.
Normally you would have something like this

		.........	.........	.........
 ISDN line	|	| S-Bus | TA or | RS232 |	|
	--------| NT1	|-------| ISDN  |-------|Router	|
		|	|	| Modem |	|	|
		`````````	`````````	`````````

Telstra's ISDN Home combines an NT1 with a TA.

The only difference between Vanilla ISDN and DoV is Vanilla ISDN
identifies itself to the Vendor network as a DATA call.

DoV is a cute hack that gets around the ruinous DATA rate by pretending
to be a local VOICE call. Telstra (and other telcos too) allow "local"
ISDN VOICE calls at a non-timed tariff.

Traverse Tech are a Local (.au) company with a well supported (Linux and
*BSD) ISDN modem lineup (internal and external models.

http://www.traverse.com.au/

> My question now is does anybody have one that they wouldn't mind parting
> with until the 13th Jan, or know where I might be able to "borrow" one
> from?

You could ring them up and grovel lots.

A couple of cons you may wish to factor in...

DoV is a hack. It is totally dependent on distance to exchange *AND*
your ISP must be almost on the same exchange as you. I don't know how far 
out the Cotter is relative to it's exchange. DO your homework lest you 
get a savage surprise. There's a magic number of 25km. but I suspect
it's measured in vendor units. (Traverse have info on this too.
http://www.traverse.com.au/general/dov.asp ).

ISDN provisioning is glacial. If you can get it. Check that no POTS
voodoo exists on your lines, basically establish your 'local' exchange
and work out the distance, and cross your fingers.

> regards,
> 
> Grant Holliday
> 

Sorry this comes across as an Ad for Traverse, I heavily researched this
around 12 months ago and they seemed remarkable clueful at the time.

Best of Luck
Daniel Smith

PS. I hate your web monkey. JS window resizes are a hangin' offence.