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TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5
reply to markysharkey

Re: [HELP] POTS to Cisco CME help!

You could end up with ISDN if you ordered two lines. But in a situation like that the telco also typically supplies an NT2 which presents you with two RJ11 sockets to plug in your analogue devices.

But in a situation like that you would probably actually be better off using an ISDN VWIC in the router and making use of full digital signalling for a better user experience (like near instantaneous call setup). This would plug in to the S interface on the NT2 IIRC - I cant remember the exact detail, been a long time since I last used ISDN.


markysharkey
Premium
join:2012-12-20
united kingd

Never done ISDN either! BUT, I have a second project on the go with 2 x ISDN2 circuits which I will have to configure. Just learning (more) new acronyms, like SPID...
I find myself at the foot of yet another steep learning curve!
--
Binary is as easy as 01 10 11


cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8
reply to TomS_

Ah, no. If you order POTS, they deliver POTS. If you order ISDN (usually much more costly), then they deliver ISDN. But I suppose things could be weird across the pond.



TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5

I would hazard a guess that most telcos reserve the right to deliver a functionally equivalent service via any means available.

If copper pairs are short there's good enough reason for them to use pair gain technologies like ISDN to deliver two POTS services if it means only one copper pair needs to be used between the exchange and the premesis.

Telcos usually have a minimum service guarantee of nothing more than a voice capable phone line. Anything else beyond that, like ADSL, isn't normally a guarantee.


markysharkey
Premium
join:2012-12-20
united kingd

Should prove interesting. My ISDN project is in the UK and is several weeks away from needing to be live. The POTS project is in Monaco and probably needs livening up week after next, so I'll know soon enough. Keep an eye out for me asking for some VERY URGENT HELP!!!
--
Binary is as easy as 01 10 11


cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8
reply to TomS_

Incorrect. ISDN and POTS are not "functionally equivalent". If the telco wants to save a copper pair by using ISDN (BRI), then it's up to them to convert it to POTS at the customer -- they don't hand off the ISDN. Bottom line, it doesn't matter how the telco gets the lines to you, what they hand you is not up to interpretation. If you ordered 2 POTS, that's what you will be delivered.

(For the record, that's how almost all T1's are done these days. Go look at your smartjack... there's two wires going into it and four coming out. The "T1" is actually and HDSL circuit, but *you* aren't handed the HDSL line.)



TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5

Did you miss the part in one of my previous replies were I said the telco also provides an "NT2"? Come on, Im not that stupid that I dont know the difference between ISDN and POTS...

Although I might have got it partly wrong, in Australia at least it was an NT1, and more specifically "NT1 plus 2". Been so long since I touched it all, but I had the right idea.

An NT1+2 presents an S interface which you could hook directly to digital equipment, but also two ports that provide functionally equivalent services to a POTS line. You plug a regular phone in, you get dial tone, each can ring and be used simultaneously and independently of the other. Voila, two POTS lines.

An NT1 presents just the S interface and is used where analogue devices are unlikely to be needed.

Now, there are also other things that can use a copper pair, perhaps in tandem with a telephone service like back to base services (monitored alarms etc), but this is going beyond the realm of POTS which is "plain old telephony service", which to me means nothing but a basic telephone service. Here you are getting in to the realms of "spectrum sharing" or what ever your local telco jargon is though.


cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8

said by TomS_:

Did you miss the part in one of my previous replies were I said the telco also provides an "NT2"?

And the OP... "The branch office will have one phone number, 2 lines. Will I be presented with two physical lines..." He asked for two lines. He'll get two lines! How the telco does it is completely irrelevant.

(he's confused by it being a single number, but more than one line. Which is no problem at all for any phone switch.)


TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5

I know its irrelevant how they deliver it.

The point of my original post was to suggest that if the two lines are delivered via ISDN then he'd probably be better off piping that ISDN service straight in to the router, rather than using analogue ports.

Why has that suggestion ended up with this conversation?