Leased line question (BT 21CN fibre)

[TonyRPH]

We have two fibres entering our building, one of which used by our "21 CN" 100mB leased line, and the other is just looped behind the outlet box.

My question is, will that 2nd connection be usable alongside the existing one? I'm pretty sure it will be, but just want confirmation.

This is the outlet box in question, with the fibre looped behind it.

[kev1974]

Wouldn't have thought so, the presence of a loop of spare cable doesn't mean anything's provisioned on it.

[bulldog5046]

Most likely.

Fibre is still run in pairs but BT now use a single fibre for RX & TX. The spare tail will most likely be ready to go in my opinion.

That doesn't mean it won't still take some monkey 3 months to get it provisioned though!

[MattyB_]

bulldog5046 said:

BT now use a single fibre for RX & TX.

How's that then? Half Duplex?

[bulldog5046]

MattyB_ said:

How's that then? Half Duplex?

I have to be honest, I have no idea....

Have a read: http://www.mrv.com/sites/default/files/white_paper...

I was baffled when I first saw an engineer do it.

[LordLoveLength]

MattyB_ said:

How's that then? Half Duplex?

Full Duplex with Freq splitting - Tx one freq/ direction . Rx another freq / other direction.
Uses very precise optical splitters at each end.
see https://en.wikipedia.org/wiki/Wavelength-division_...