Thanks to all who replied; I'm still not sure what to do. I've had the
same problem with two different Interware 320 MHz G3 cards, and they are
not "overclocked", to my knowledge.
On any given week, my serial port is either:
1. working great
2. intermittent
3. not working at all (failed solid).
In the past year, I've seen each of these about 33% of the time.
To anyone interested in the details, the failure is that the receive data
(into the Mac) works fine, but the transmit data likes to stick on the
"MARK". When an application activates the port, a steady "MARK" voltage
appears on the TD+ and TD- output pins (this is normal), but it does not
always turn to "SPACE" when required to transmit data. It may fail
solidly, or it may work for a few seconds, on and off. In terminal
emulation, characters get skipped and garbled. Sending MIDI data to a
sound module makes some really wild sounds. In all caes, the application
does not seem to know that anything is wrong; it thinks it is sending
data OK.
I have had it repaired 2-4 times by AppleCare when it failed solid
(always stuck on MARK, never turns to SPACE). Sometimes it comes back
fixed, and sometimes not. One time they fixed it by replacing the
I/O-Power Supply card. The other times, no one knows. Each time, after
it's fixed, it works for a few weeks. Then it becomes intermittent for a
day, or a week or a month. Eventually, it fails solidly.
I have done alot of testing with and without system extensions, virtual
memory, background applications and am certain that it is not software. I
have created an Extensions Set which contains only one extension, the
Serial Tool which is necessary for applications to drive the serial port.
On numerous occasions, I have found that using this Extensions Set
instead of my regular Extensions Set makes absolutely no difference. I
have also tried resetting the power manager, PRAM, etc. - none of these
has ever had any effect.
I normally network this computer using a Dayna 10BaseT Communicard. It
makes no difference to the problem whether the Communicard is in or out.
I always keep AppleTalk set to use the Communicard. I use the serial
port for MIDI, file transfer with the serial port on a Windows computer,
and occasionally, a modem.
It failed solidly at the beginning of November, so I sent the unit to
AppleCare. I received it back from AppleCare on Nov 30, 2000. As usual,
they gave no indication of what they did or did not do to it. I
reinstalled my 10BaseT PCMCIA card, reset the clock, switched AppleTalk
from serial port to 10BaseT, connected my loopback plug to the serial
port, launched TechTool Pro, and ran the serial port test.
Well, it seems that this time AppleCare improved it from "failed solid"
to typical "intermittent". On the first try, it failed. On the second
try, it passed. On many subsequent trials, it usually failed but
sometimes passed. I then launched a ClarisWorks Communication document
running terminal emulation, connected the serial port to a desktop PC
also running terminal emulation, and attempted to type messages back and
forth between the two computers at 57.6 Kb/sec. As before, data from the
PC to this powerbook always worked without errors, but data from this
powerbook to the PC was intermittent. Typically, it will transmit 95%
of the characters for a couple of lines, skipping a few, then we'll get a
few garbled characters, then it will quit for some tens of seconds, then
it will start working again, etc., etc. The same thing happens if I try
to "echo" the characters back to the powerbook with my loopback plug. I
then tried to transfer some files between the two computers using Star
Gate, a shareware application for this purpose. Again, the result was
intermittent. It did work for awhile; as a matter of fact I was able to
download the SerialDMA 2.1 extension from the Apple web site to the PC
and transfer to this powerbook using Star Gate via the serial port.
During the next hour or so, I tried all three tests (TechTool, terminal
emulation and Star Gate) with various combinations of all system
extensions, serial and comm tool extensions only, and with and without
SerialDMA 2.1. I also tried turning the Interware's "Backside Cache" on
and off. The result of these tests is: currently intermittent under all
conditions. None of these system software changes made any difference
whatsoever.
Jerry
This is in reply to the message (quoted below) from
[EMAIL PROTECTED]:
>From: [EMAIL PROTECTED]
>Sender: [EMAIL PROTECTED]
>Reply-to: [EMAIL PROTECTED]
>To: [EMAIL PROTECTED]
>>Having never had any sort of problem with the serial port (and I've
>>used it heavily) and having seen two similar reports of trouble on
>>G3-320 upgraded machines, I'm becoming suspicious of the clock
>>crystal on your 320MHz card (and Jerry's). Bad clocking will mess
>
>I did not suggest that most problems with the serial port began with the
>GS320MHz upgrade nor that the stylewriter was a particular problem. The
>occasional difficulties with a stylewriter are not greater than with a
>2300 or other duo with a single serial/modem port. That is also true of
>connecting to my digital camera vie serial port. I also did not suggest
>that the problems with using the Epson Stylus printer and hotsyncing my
>Palm was related to the G3320MHz upgrade.
>
> What I did say is that the ethernet connection via my GV Modem/ethernet
>PC Card has not worked since upgrading to the GS 320MHz. I also said
>that have never had any problems using a USB PC Card to print with my
>Epson Stylus nor in using IrDA to sync my Palm. My point is that the
>2400c offers great options to the flaky serial port.
>
>Stan Bratton
Jerry Krinock
San Jose, CA
Claris Em@iler 2.3 for Macintosh
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