multimode and single mode fiber cables

If it is a "single mode gbic" then it is not going to be 1000Base-SX as -SX is not supported on single mode.

If you are going "between 2 buildings" then the distance might not be all that far -- not far enough to require -SZ or wave division, both of which require single mode.

You might, then just happen to be using -LX -- and LX *is* supported on both single mode and multimode; for single mode, the maximum segment length is 550 m -- though for more than 300 m it needs a mode-conditioning cable to launch the light closer to the centre of the fibre.

If they're SX then you're going to have to use MM fibre.

Chris.

I agree:-

The Cisco 1000BASE-SX GBIC (WS-G5484) operates on ordinary multimode fiber (MMF) optic link spans up to 1815 feet (550 m) long.

SX GBICS are Multimode.

Cable colour is NO indication of specification.

MM 62.5/125 50/125

SM 9/125 [sometimes 8 or 8.5 instead of 9]

These figures are usually prnted on the cable every 1 or 2 metres. They refer to the core Inner/Outer diameter in micro-metres.

You need to make sure that your patch leads and cable are all of the same type. (i.e. all 50 or all 62.5) for any one run.

Oops , I am sorry the GBICs are actually LX gbics part number

WS-G5486

Would That require single mode fiber cables (yellow)?

No. See for example table 3 of