[Trlog] Serial/parallel port interaction; USB to serial converter recommendations

[Pete Smith]

I'm reporting this weird problem to these two lists in the hope that having 
it in the archive may save someone weeks of hair-pulling frustration.  If 
you don't care to read further, I can cut to the chase and tell you that it 
has a sort-of happy ending.

I bought a Manhattan PCI serial port card for my Win98SE PC (part no. 
165273 with Sunix chipset), in order to be able to have an additional 
serial port for Winkey (the two on-board serial ports were already 
controlling radios).  I installed it, and everything seemed to be running 
fine on the serial port side, but then I tried to control my TopTen DX 
Doubler SO2R box with the *parallel* port.  To my dismay, the PTT line for 
Radio 1 was being held high, meaning that the radio was stuck in 
Transmit.  I could command the controller to switch to Radio 2, but after a 
variable period of anything from 1/2 to ~7 seconds, it would switch itself 
back to Radio 1 and the PTT would switch on again.  There was no difference 
in the port's behavior whether the N1MM software was running or not.  Very 
weird.

My first thought was the DXD, and it went out to TopTen for 
trouble-shooting, but nothing was found.  Next (I should have done this 
first),I verified that the voltages on pins 14 and 16 of the LPT port were 
consistent with the switching behavior.  Then the computer began to 
malfunction (seeming to overheat), so I thought, OK, it's probably hardware.

Bought a new computer, running under XP, installed the N1MM software with 
the appropriate port driver (dlportio), and the LPT port switching was 
working fine, so I started moving hardware across from the old PC.  I 
really needed the serial port card, because the new machine only had one 
serial port.  Right after I installed the serial card's driver, I tried 
N1MM.  Imagine my surprise -- the LPT port problem had recurred, on a 
completely different machine, under a different operating system.

I tried uninstalling the drivers for the serial card, and deleting it from 
the hardware profile, all to no avail.  Then K1TTT told me about the 
"system restore" functionality in XP, and that proved to be the charm.  I 
was able to restore the machine to the state immediately before the driver 
installation, and that restored the LPT port to proper operation.  I have 
reported the problem to Manhattan, and am hoping, but not really expecting, 
that they will have a fix already in hand.

This is what I mean about a sort-of happy ending.  I need to find some 
other way to provide the two serial ports I need, and am leaning toward a 
USB to serial converter.  I'd appreciate any recommendations of a unit that 
is reasonably priced, has adequate RF immunity at HF, and will handle 7 and 
8-bit communications so that I'll be able to run digital modes if I decide 
I want to.

Thanks for listening.

73, Pete N4ZR
The World HF Contest Station Database
was updated on April 26, 2004
2706 contest stations at
www.pvrc.org/WCSD/WCSDsearch.htm