Setting up the Hardware

Most PC interface for serial data exchange follow the RS-232 standard. For this purpose eleven of the RS-232 signals are required. Furthermore, there is a 9 pin connection defined by IBM which has been used in this project.

On the 9-pin connector the protective ground and the signal for the data signal rate are missing as compared to RS-232, but the remaining 9-signals are sufficient for a serial asynchronous data exchange between two DTEs . The pins 3/2 and 2/3 transfer the data signal, the rest of the connections are intended for the control signals.

In the above connection diagram Pin 2 is receive, the Pin 3 is transmit and Pin 5 is ground. Join Pin 5 of both connectors with a cable (this is the common ground). Pin 2 of one connector should be joined with Pin 3 of the other and viceversa (This forms RxT and TxR connections).