BRI ISDN Termination

[Deanski32]

Attention all Mitel Guru's,
This is my 1st post. I'm about to install a Mitel 3300 CXi II with Quad BRI card I have tested it in the Lab and all is working fine however I can only test the BRI via a VOIP-to-BRI gateway device as I don't have an ISDN connection in the lab. Here in Australia ISDN connections incorporate an NT1 network termination device which converts the 2 wire "U" line from the CO exchange - to 4 wire "S/T" line. There is also a choice of either Point-to-Point or Point-to-MultiPoint protocol and in my case I would use Point-to-Point as the 3300 is the only device connecting to the S0 line. Now with the NT1 device which is supplied by the ITSP has DIP switch to configure 100ohm termination for the S0 line and allows several different variations depending on wether PP or PMP.
My question is do I require termination resistors on the S0 End or does the Mitel BRI card provide internal termination.
Also the distance from the NT1-to-Mitel is under <10M.
Hopefully someone can enlighten me on this conundrum.

[sarond]

I have only ever installed to Telstra supplied NT1 but all I need to do is connect patch lead straight from NT1 to Quad BRI no need for any terminating devices.
Have carrier program as Point to Point and away you go.

[Deanski32]

Thanks Sarond just what I needed to hear. I was hoping for a simple solution, sometimes it's hard to find information on these things lucky we have forums. 

[Deanski32]

Sarond when you say "patch lead" would this be straight or cross over?

[wiseguy]

Straight in your case. Crossed is for device connections.

[sarond]

Yes straight standard ethernet cable.

[Deanski32]

Thank you Sarond & Wiseguy.

[Deanski32]

Hi all,
Just thought I would report back on my progress and for anyone else stumbling across this post may find it helpful.
I'm pleased to report that I now have a new ISDN line + NT1 termination unit installed and working with all test completed , and so far no issue to report. I did however notice on the supplied NT1 instructions it shows the use of so called "Krone Bus-End Terminator" which is designed to be plugged into the 2nd S/T port of the NT1 if there is only 1 TE device used and the TE does not have internal termination.
I assume that when the Mitel ISDN Protocol Assignment bus-type: if set as "T" Trunk this tells software to apply termination internally at the BRI port, and therefore no additional external terminator would be required.
I looked at the Mitel documetation and found mention of software termination for T1/E1 card but no mention for Quad-BRI. Anyway just thought I would run it past you all and see if any one else has any thoughts, included a page of the NT1 doc.

[x-man]

In the UK I have never needed to terminate the S bus as I have assumed that the as its mainly PtP we use its only going to have the Mitel on the end of it and I was under the impression that thge quad bri did the termination.

[Deanski32]

I believe the UK and us Ozzies use the same ISDN ESTI standards so I'm sure your view is correct thank's X-man.

[sarond]

I have never had to terminate the connection either.
This is based on Telstra supplied NT1 devices Point to Point.
I believe if you have Point to Multipoint then you get an SBus which multiple devices can use. In this case you will probably need a terminator.

[x-man]

From experience of the Mitel iMAGINATION which used the same S bus as BT use (it was designed by Philips in the beginning) you can get away with no termination on PtP over short distances and good cabling. imagination phones were supposed to be terminated but TBH we very rarely had to unless the phone was at the end of a very long cable.

However the official line is that you need to terminate the last piece of equipment on a PtMP S bus. And I would do so.