OUTPUT, ENTER, and TRANSFER are explained in the "General Input and Output" section. Before data can be exchanged, the serial driver must be loaded, the computer and device must be cabled together correctly and the RS-232 communications parameters must be set correctly on both the computer and the device.
The CONTROL and STATUS statements read or set various interface parameters, such as baud rate, character format, etc. CONTROL and STATUS examples given in this section assume that the serial interface has an ISC of 9. This is the default ISC for the first serial port. If you are using another port, or if you have changed the default ISC, you will use a value other than 9. The following example reads status register 3 of ISC 9.
PRINT "COM1 baud rate is ";STATUS(9,3)
The READIO and WRITEIO statements read or set hardware registers. These registers are typically quite different than the hardware registers on an HP BASIC RS-232 Interface. You should not attempt to use these registers unless you are familiar with the RS-232C hardware. You should also not mix use of READIO/WRITEIO with STATUS/CONTROL statements. Using STATUS/CONTROL statements is preferred.
