Setting this variable to setPulseOnTXD(2)
causes adapter to generate a PULSE on TXD pin of serial port 2.
The duration in the prototype implementation will be 1 second.
Setting this value to noSetPulseOnTXD(1) has no
effect.
The value noSetPulseOnTXD(1) will always be returned
when the variable is read.
Setting this value to setTXDLow(3), or setTXDHigh(4) will keep TXD
always low or high respectively.