Hi Idiaz,

ST fiber might mean you have legacy ST connectors from a 10FL fiber infrastructure, maybe, dont know from the information supplied?

The only fiber interface card I have seen for the 2851 is the HWIC-!GE-SFP interface card with the following link directing you to the datasheet on that product.

http://www.cisco.com/en/US/prod/collateral/routers/ps5854/product_data_sheet0900aecd8016be8d_ps5949_Products_Data_Sheet.html

SFP can be terminated  with this card, however they  support LC  not ST connectors. If you want gigabit connectivity and utilize more modern SFP, does it make more sense for you to re-terminate the fiber connectors and replace the ST connectors with  LC connectors.

But, there are other  solutions to connectivity issues, but I could not answer your question, only guess as to what you really need?

Minimum information that would be useful to know, would be;

1. Speed required of the fiber link?

2. Distance required for fiber link?

3. Type of fiber in place  9um or 50um or 62.5um ?

Regards Dave