The Model 214A allows full duplex transmission up to 38.4 KBPS over a single twisted. Scrambled data is differentially encoded which serves to make the data on the line polarity independent. The time base for both modems is referenced to a highly stable crystal clock and is phase locked to the received data stream. Transformer coupling to the line provides the advantages of ground loop elimination and increased resistance to common mode noise. The Model 214A is available with a male or female DB25 connector and both an RJ-11 and screw terminals for the line.
Power is supplied from a small wall mounted transformer.
Use of the Fastwire Modem on DTE or DCE ports is accomplished by positioning a slide switch to the appropriate position. This has the effect of reversing pins 2 and 3 of the RS-232 interface. The Fastwire Modem is also equipped with a Ready LED which, when illuminated, informs the user that the link between 214A's is established and both modems are operational.