Ha ha ......... it all depends on where the tie-cables are positioned in the PCP. Generally, they will be on the far right-hand side of the PCP, but can be sited on the far left if space requirements dictate.
By way of an example, if there are 600 existing E and D sides in the Copper Cab, the new ties will be allocated as E and D 601-700. So, if the installation engineers mapping is ........ E312 to D623 --- E623 to D478 ........ this means the circuit is the 23rd port to be made 'live'.
This means the existing routing in the copper cab was .... E312 to D478.
We do have what is called 'Straight pinned' routings, whereby the existing copper E and D sides are the same ....... so the engineers mapping details could then show as ....... E312 to D623 --- E623 to D312 .......... again, this means the Fibre port is port 23 and the original routing was '312 straight-pinned'.
What I'm labouring to say, is if Bossian manages a peek at the engineers field book, he should be looking for a 'pair' of numbers to find the number port he has been allocated. If there are 2 sets of numbered 'pairs', it would usually be the higher numbered pair that indicates the fibre port.
Hope this makes sense ??