I am working with my service providers to provision 2 new 1GB circuits. The circuits are with 2 different providers, COLT and EUNetworks.
They both tell me they will be delivering managed dark fiber, COLT say this will be a 1310 circuit (i am assuming they mean wave length). EU say they can deliver as 1310 or 1490. I would assume if I am getting a 1310 circuit I would use transciever 1000BASE-BX-U based on document http://www.cisco.com/en/US/prod/collateral/modules/ps5455/ps6577/product_data_sheet0900aecd8033f885.html however this document confused me with the following line:
1000BASE-BX10-D transmits a 1490-nm channel and receives a 1310-nm signal, whereas 1000BASE-BX10-U transmits at a 1310-nm wavelength and receives a 1490-nm signal.
Can anyone advise me which I should use? If I don't have enough information here can you tell me what question I should ask the service providers to find out (other than asking them which transceiver to actually use).