I am confused with all this RS-232 jargon. I have read the section in the VIC-20 Programmer's Reference Guide, but it seems to be written for someone who is already familiar with RS-232. I'd like to interface a serial printer, and also a bar code concentrator – that's a buffer memory which stores ASCII received from several bar code scanning stations.
First, check COMPUTE! (August 1982) "VIC-20 Communications/The RS-232 Interface" applies to both the VIC and the 64. In October, "Ask the Readers" gives more information on interfacing printer devices.
However, neither of these references gives all the answers. Right now, there are users working on problems associated with the "full handshake" option, which doesn't work at all on the VIC and which has problems on the 64. Until Commodore releases a new ROM to fix the problem on either or both machines, users must go after the problem themselves by using machine language programming on an interrupt level – and that's a complex job. COMPUTE! should soon be able to publish a success story on how it's done.