Aucbvax.1858 fa.info-cpm utzoo!duke!decvax!ucbvax!fylstra.tsca@SRI-Unix Tue Jun 23 02:30:47 1981 RS-232 FTP at 9600 baud This may have been attempted before, but I thought it sufficiently interesting to report to everyone... This evening, Term Kovattana and I succeeded in using the MODEM2 program for reliably transferring files between CP/M systems over an RS-232 link at 9600 baud. The two systems were an S-100 system (Cromemco Z2-D) with 8 inch floppy disks and a HeathKit H89 with 5 inch floppy disks. We used the latest version, [mc]cpm;modem206 asm, modified as appropriate for the corresponding serial ports. This program transmits binary files in packets consisting of a header, sequence number, data, and a checksum, and provides a simple ack/nak/timeout protocol. We used the "quiet" mode at each end of the connection to avoid problems caused by program status messages garbaging the transmission. It is a real pleasure to see a 10K file zipping between systems in seconds! Incidentally, the initial download from the Z2 to the H89 was accomplished using standard CP/M tools as follows: Z2 end H89 end pip crt:=ftp89.hex pip ftp89.hx=rdr:[b] pip crt:=con: ctl-S ctl-Z ; file at this end is flushed pip crt:=eof: ; file at this end is closed ren ftp89.hex=ftp89.hx The [b] switch causes the receiving end to buffer the 10K hex file in memory until the ctl-S is received as a result of the second command line at the sending end. Finally, the third command line transmits a ctl-Z which causes the receiving end to close its file. The '.hx' file extension is used to prevent the receiving PIP from wasting time verifying Intel Hex format while reading the file, and is subsequently renamed to '.hex'. Next step...attempt to transfer files between a TOPS-20 and a CP/M system over a hard line at 9600 baud. Dave Fylstra ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.