The source of the transmitter, IF-E96 emitter has a peak
wavelength of 650nm which lies in the minimum
attenuation window of plastic multimode fiber. The
maximum optical loss for 1km of perfluorinated fiber using
this source is less than 2.4dB[1]. And the IF-E96 supports
high speeds up to 5Mbps because low transition delays.
Hence it can support the maximum possible bit rate of
RS232. The plastic connector in built with IF-E96 will
satisfactorily couple -7dB optical power to fiber with
minimum coupling loss.