Computer Busses

27

RS-232 Programming using Visual Basic

27.1 Introduction

This chapter discusses how Visual Basic can be used to access serial communication functions. Windows hides much of the complexity of serial communications and automatically puts any received characters in a receive buffer and characters sent into a transmission buffer. The receive buffer can be read by the program whenever it has time and the transmit buffer is emptied when it is free to send characters.

27.2 Properties

The Comm component is added to a form whenever serial communications are required (as shown in left-hand side of Figure 27.1). The right-hand side of Figure 27.1 shows its properties. By default, the first created object is named MSComm1 (the second is named MSComm2, and so ...