The 3503 model is manufactured by SI Tech, and is an optical mini bit-driver® with full duplex synchronous DC to 9.6 Kbps, asynchronous DC to 19.2 Kbps with control signals. It has maximum distance capable from 6600 ft, and can operate at temperature ranging from -20°C to +85°C.
The unit has transmission line interface of SMA connector that is standard for interface with fiber optic duplex cable. It has core optical fiber of 1 microwatt in 15 dB power budget at 850 nanometers. It also has a metal cover with dimensions of 4.25 X 10.2 X 2.2 cm, and power rating of 110/230 V AC to 12 V DC with mass of 0.37 lbs or 190 grams.