The 100BASE-FX ports on the 2950C-24 and on the 24-, 48-, or 4-port modules for the 4507R are meant to be used for transmission over multimode fiber. This fiber can be either 62.5/125 micron or 50/125 micron type.
Your equipment will not work with the single-mode fiber that you have.
You have two choices: either use a pair of 100BASE-FX multimode to 100BASE-FX single-mode media converters (Transition Networks is one of many vendors that make these; http://www.transition.com ), or install new multimode cable. The media converters (part number F-SM-MM-02) will cost you about US$1,300 for two, not including patch cables. Not sure how much it would cost to install new multimode cable, but I bet it is more than $1,300 plus patches.
Light source on the 2950C-24 is 1300nm wavelength LED. Connector type is SC.
On 62.5/125 micron cable, optical transmitter power ranges from -20 to -14dBm; optical receiver sensitivity ranges from -33.5 to -11.8 dBm; link budget is 13.5dB.
On 50/125 micron cable, optical transmitter power ranges from -23.5 to -14dBm; optical receiver sensitivity ranges from -33.5 to -11.8 dBm; link budget is 10dB.
I think is it safe to assume that the optics characteristics on the 4507R are the pretty much the same, since they are standard 100BASE-FX ports; I can't find any optical power information about them. Connector type is MT-RJ, however. So you may need some fiber patch cables with custom connectors (MT-RJ at one end, SC at the other).
Hope this helps.
