13.  MODEM



INPAUX$


With the command INPAUX$ the internal RS232-buffer is read and at the same 
time cleared. You can find the address of the input-buffer with XBIOS 14 
(Iorec):

     adr.in%=LPEEK(XBIOS(14,0))

The output-buffer can be located with:

     adr.out%=LPEEK(XBIOS(14,0)+14)



INP

If you use INP(1) to read incoming bytes, you should always check with 
INP?(1) if the RS232-buffer contains data. 



Rsconf (XBIOS 15)


With XBIOS 15 (Rsconf) you can change the RS232-parameters. A few 
baudrates:

     0 - 19200 baud
     1 -  9600 baud
     4 -  2400 baud
     7 -  1200 baud
     9 -   300 baud
    14 -    75 baud

Use -1 for parameters you don't want to change. Due to a TOS-bug, you 
can't use 75 baud, because '14' results in 120 baud. Also, the old TOS 
(pre-Blitter age) can't handle hardware handshake with RTS/CTS-signals. 
Atari has released a bug-fix that should enable any TOS to use RTS/CTS. 
Software handshaking (XON/XOFF) functions properly. The default after 
power-up is no handshake protocol.


It should be possible to use 75 baud by changing Timer D with XBIOS 31 
(Xbtimer), but I've never tested this:

     ~XBIOS(31,3,3,64,L:-1)



                        Procedures (CHAPTER.13)


Baud                                                                  BAUD
Change the baudrate:
     @baud(2400)