mcb@cmu-cs-k.ARPA (Michael Browne) (01/27/85)
I seem to be having some problem using my 1200 baud modem with the C64. Every so often, I get a burst of garbage. This is not a problem with the telephone line or the modem (I've checked both with another computer). Is anybody else having similar problems, or is there something wrong with my C64? --Mike -- uucp: ..!seismo!cmu-cs-k!mcb arpa: mcb@cmu-cs-k.ARPA
@RUTGERS.ARPA:prindle@nadc (01/28/85)
From: prindle@NADC Running a 1200 baud modem on the C64 requires more than a little sorcery, I'm afraid. Simply plugging the value 8 into the baud rate register won't do it. You will appear to transmit fine, but blocks of data coming back will surely be periodically damaged. But reliable 1200 baud full duplex communi- cation is definitely possible, just rather tricky. Many early releases of commercial telecom programs for the 64 (including Compuserve's VIDTEX) fell prey to this trap. The full solution is too complicated to explain here, but to put you on the right track, try opening the RS-232 channel with the baud rate code set to zero, and with two additional characters in the name equal to 60 and 1. An equivalent in BASIC: open 2,2,0,chr$(0)+chr$(0)+chr$(60)+chr$(1) This will cure the fundamental problem - you may soon find some others; welcome to the wonderful world of Commodore!
percus@acf4.UUCP (Allon G. Percus) (01/30/85)
> I seem to be having some problem using my 1200 baud modem with the C64. > Every so often, I get a burst of garbage. This is not a problem with the > telephone line or the modem (I've checked both with another computer). Is > anybody else having similar problems, or is there something wrong with my > C64? I had a similar problem when I tried writing an inefficient terminal program in BASIC. Apparently, it didn't read the characters as fast as they came in, and the interface buffer became overloaded. Remember, this was BASIC, but I was only running at 300 baud, so unless you have some rather efficient ML code, problems like this are to be expected. I would look for a different terminal program, one which advertises that it can be used with 1200 baud, or else write something myself which sends an X-OFF signal after every few characters, giving the 64 some time to "digest" the data, and then sends an X-ON, telling the host to continue where it left off. A. G. Percus (ARPA) percus@nyu-acf4 (NYU) percus.acf4 (UUCP) ...!ihnp4!cmcl2!acf4!percus
rph1283@ritcv.UUCP (Robert P. Herloski) (02/01/85)
> > I seem to be having some problem using my 1200 baud modem with the C64. > > Every so often, I get a burst of garbage. This is not a problem with the > > telephone line or the modem (I've checked both with another computer). Is > > anybody else having similar problems, or is there something wrong with my > > C64? > > I had a similar problem when I tried writing an inefficient terminal > program in BASIC. Apparently, it didn't read the characters as fast > as they came in, and the interface buffer became overloaded. > Remember, this was BASIC, but I was only running at 300 baud, so > unless you have some rather efficient ML code, problems like > this are to be expected. I would look for a different terminal > program, one which advertises that it can be used with 1200 baud, > or else write something myself which sends an X-OFF signal > after every few characters, giving the 64 some time to "digest" > the data, and then sends an X-ON, telling the host to continue > where it left off. > > A. G. Percus > (ARPA) percus@nyu-acf4 > (NYU) percus.acf4 > (UUCP) ...!ihnp4!cmcl2!acf4!percus A kludge way around this problem, if indeed the problem is buffer overflow, is to tell the system with which you're communicating to pause a short time after a CR. In UNIX, this is done via: %stty {cr0,cr1,cr2,cr3}, where: cr0 - no pause cr1 or cr2 or cr3 - increasing pause duration. This, by the way, works well with the "software" 80 column terminal programs that take a bit of time to paint the screen, and may lose some characters at 1200 baud if not explicitly compensated for. For example, Screen-80 doesn't seem to be able to draw characters at the bottom of the screen (with scrolling) at 120 cps. ------------------------------------------------------------------------------ -- Bob Herloski ..!rochester!ritcv!rph1283
slb@bnl.UUCP (Sanford L. Barr at Brookhaven National Labs, L.I.) (02/03/85)
> I seem to be having some problem using my 1200 baud modem with the C64. > Every so often, I get a burst of garbage. This is not a problem with the > telephone line or the modem (I've checked both with another computer). Is > anybody else having similar problems, or is there something wrong with my > C64? > --Mike > -- > uucp: ..!seismo!cmu-cs-k!mcb > arpa: mcb@cmu-cs-k.ARPA Ma Bell and 1200 baud don't always mix. Using a 1200 baud line with an average everyday voice line will occasionally bring up some garbage on the screen. Normally this garbage only effects what you see on the screen and dosen't get transmitted to the system you're hooked into. The only way to get around this is to get a dedicated 1200 baud line (the line runs at 2400 then) which will cost you a pretty penny. -- Sanford L. Barr Famous designer of the Write Only Memory. -- -- ..!decvax!philabs!sbcs!bnl!slb
calway@ecsvax.UUCP (James Calloway) (02/19/85)
x
Does anyone know the bugfix for the C64's RS-232 software? I read it somewhere
but don't remember where. Seems that it was fairly simple and corrected the
bulk of the machine's 1200-baud problems.
--
James Calloway
The News and Observer
Box 191
Raleigh, N.C. 27602
(919) 829-4570
{akgua,decvax}!mcnc!ecsvax!calway