ISDN PRI Fiber Usage

[OrangeMonkey]

I am researching a billing issue from our ISDN provider Level(3) Communications. They did an account grooming and say we have 2 ISDN PRI connections instead of the 1 we believe we have. I have searched the Internet but I can't find a diagram of these connections. On the card (Fujitsu FC9612H3M1) where the fiber connects there are 2 connections. Am I correct in assuming 1 fiber is 23 D channels and the other fiber is 1 B Channel? OR is it possible that 1 fiber carries all 24 channels and the other fiber has another 24 channels resulting in 2 ISDN PRI? Your help is most appreciated.

 

[johnpoole]

you don't need a second fiber for the d.. a pri is 156kb, 23 b's and a d each 64kb.. it can be a fiber or copper. you don't have an external connection for the d

john poole
bellsouth business
columbia,sc

 

[OrangeMonkey]

OK... so I guess there are a lot of options but I have to ask the question again. If you walked into my telephone equipment room and saw that Fujitsu card I mentioned above and there were two optical fibers connected to it would you say "Hey, you've got ONE ISDN PRI line" or would you say "Wow, you've got TWO ISDN PRI lines"?

 

[golfdoctor]

I agree with John,

Not sure about the Fujitsu Card however under normal situations fibre is configured such that 1 strand or connection is for TX and the other strand is for RX, thus the 2 connectors at one end of your interface equipment.

In order to facilitate TX/RX on a single fibre strand you would require an interface associated with the fibre/equipment which basically is capable of TX at freq/wavelength "A" and RX at freq/wavelength "B". This equipment would require a "match" at the other end with the opposite freq/wavelength parameters. These devices are available and becoming more prominent however no idea about your Fujitsu Card. Seen them more for IP/ATM type scenarios.

Walking into the TC I would say you have a "normal fibre "Duplex' type connection which tells a person nothing as to the amount of T1's which are associated with the peripheral equipment.

Just some food for thought


TGD

 

[golfdoctor]

I agree with John,

Not sure about the Fujitsu Card however under normal situations fibre is configured such that 1 strand or connection is for TX and the other strand is for RX, thus the 2 connectors at one end of your interface equipment.

In order to facilitate TX/RX on a single fibre strand you would require an interface associated with the fibre/equipment which basically is capable of TX at freq/wavelength "A" and RX at freq/wavelength "B". This equipment would require a "match" at the other end with the opposite freq/wavelength parameters.

Walking into the TC I would say you have a "normal fibre "Duplex' type connection which tells a person nothing as to the amount of T1's which are associated with the peripheral equipment.

Just some food for thought


TGD

 

[OrangeMonkey]

OK, the account manager for Level(3) said they did a switch audit which sounds like they have a way of seeing the cards and connections remotely. But if a card which is normally used for ISDN PRI was in the switch but it was being used for a different purpose like communicating with a microwave system on our roof they may have read the results wrong. When I first talked to this lady I asked her if we could go the my equipment room and have her point to this stuff and she said 'No I don't do that'. I guess its time to use High Tech. I'll make a video for her of the equipment room and microwave rack on the roof and she can get someone to evaluate the situation. Of course I could use the Low Tech reverse christmas tree lighting technique... Thats the one where you disconnect stuff and see who complains. I'll flip a coin. Thanks for your help.

 

[PackRat1]

What I would do is request the circuit number for the two circuits they say you have and see if you can locate the one that you do not have. The Demarc should (and I say should) be labeled with the circuit numbers. It may be there and not connected to anything. Also my limited experience with the Fujitsu card are that they have a TX and RX connection. I havn't worked with them in a couple of years though.

 

[OrangeMonkey]

Thanks for the card info. As far as circuit IDs I've already asked and guess what Level(3) doesn't use them. The account manager says they only use phone numbers. The Demarc has a bunch of numbers on the cover which we acknowledge as ours but that doesn't equate to how many ISDN lines they supplied to make them active. I have just emailed the account manager with two options. ( I haven't mentioned the Christmas Light Option Yet!) I asked her to either send someone out here who can show me point by point what they say we have or I can photograph or video the rack and microwave equipment which is connected to the second Fujitsu card and I'll email it to her. Then she can have anyone in the world view the evidence and make a judgement on what is here.