Work being done on line - Not sure what terms mean :s

Hi all - I'm currently having some work done on my telephone line at my local exchange. I'm told that the work being carried out is a 'pair exchange' or a 'type pair exchange' and also that they are performing/putting a 'jumper' on the line?

Problem is SKY couldn't explain what these mean so I don't have a clue what they're doing. If anyone can shed any light on this it would be great.

Currently on SKY Unlimited if it helps.

Thanks

Apologies - it turned into an essay!

I think you mean "tie pair change". Tie pair and jumper are used interchangeably these days, which is a shame as they are two different things.

All telephone lines come into the BT exchange and connect to a large frame (main distribution frame or MDF). This is basically a convenient and structured place from which the various lines can be easily onward connected to whatever equipment within the exchange they need to be.

In the case of an LLU provider (e.g. Sky) - they will have their equipment installed in a specific part of the exchange set aside for LLU operators. Their equipment installation has a similar but much smaller structured cabling frame (handover distribution frame), which on one side is permanently cabled up to their LLU equipment and on the other offers rows of connectors for people's lines to be connected to.

Rather than every time someone orders a Sky LLU service, Openreach having to run cables from the MDF to the HDF - which may be some distance / floors away - there is permanent cabling installed that connects the MDF to the HDF put in place. At either end this is terminated on rows of empty connectors. The cables between the frames are called Tie Cables, as they tie the frames together. These cables consist of 100 pairs of copper wires - hence these are termed "tie pairs".

Now - when someone orders a Sky LLU service - all the engineer has to do is at the MDF connect customer's line to the connectors for the Sky tie cable there, then at the far end - the HDF, connect between the tie pair connector to the connector that feeds the LLU equipment. The inter-connections between these sets of connectors at either frame are done with shorter runs of individual copper pair - these are called "jumpers".

Most frequently - when an LLU ISP says they are doing a "tie pair change" - it effectively means they are connecting your line to a different port on their equipment. It's called a "tie pair change" as when the order goes to Openreach to do the work - Sky just request they move your lline to a different tie pair on their equipment.

Openreach may just change the jumper between the two connectors on the HDF. Or they may do that AND elect to use a different tie pair between the frames AND consequently have to move the jumper to the correct connector at the HDF end of that tie cable.


I think Kitz explains it better than me..... pictures always help! Try here:

http://www.kitz.co.uk/adsl/telephone_exchange.htm#LLU

Haha, no worries GeeTee, that's just what I was after tbh. Gives me a much better idea of what they're doing now. Thanks

Just another thing you might be able to help me with? I currently have a lot of noise on my line and had an engineer vist a few days ago that repaired a 'HR Dis' problem which didn't make any difference to anything. Do you know if these procedures are likely to reduce the noise at all? If not, can you suggest anything that could improve things?

The reason I'm trying to get it down is because I'm 375m from the exchange with a downstream attenuation of 15.0 dB but with a noise margin of 7.5 ish at 11.5mb, so really would like to hit 15-16mb on this line, if possible.

Cheers