[GreenKeys] WinPsk31 with TTY Printer Driver

[Robert McConnell]

At 1/2/03 07:32 PM -0500, Richard M. Gillingham wrote:
>I took a look at this, and I'm enthusiastic.  But (always but) Nowadays 
>the PCs come with only one RS232 port installed, and at least 4 (my new 
>Dell has 6) USB ports.  What's the drill to either convert USB to RS232, 
>or to port the software to USB??  We're faced with an evolving  PC 
>environment.  My RS232 port is already being used for computer control of 
>my transceiver, and I'm not pleased to hot swap the plugs......  I had to 
>scrap my P38 card too, because of a lack of a slot for it.  All PCI slots 
>now...   What's a poor op to do??
>
>Thanks for writing neat software.
>73
>Gil, W1RG

Hi Gil,

What I do is keep some old computers around to handle the "obsolete" 
hardware. It's pretty simple to keep three or four stacked under the desk 
with a KVM switch so they can all be controlled with a single keyboard, 
monitor and mouse. I see no reason to upgrade to the latest hardware (or 
software) just to keep up with the Jones boys. I also keep a few 386 and 
486 laptops handy to use as terminals. I even have one Compaq Portable-III 
at work. That's a 12MHz 286 with the amber display. It has a backpack with 
two ISA slots, MS-DOS 5 and Telix 3.15 as the primary application. It 
hasn't been out of the office for several years now, but it still rests in 
its original carrying case. Hey, they don't cost us anything. The IT techs 
know to stop and see me before they take anything to the recycle bin.

The biggest problem with the USB to anything converters is on the software 
side. Under DOS and MSWindows prior to NT, all applications could access 
the hardware directly, with no interference from the OS. NT and later 
systems block direct access and require the installation of drivers that 
hide the hardware from you. So the application needs to talk to the 
drivers, and can no longer use the hardware directly. This is both good and 
bad news. Good news because it shouldn't make any difference whether you 
use a serial port on the motherboard, through a multi-port adapter, an 
Ethernet connected terminal server or a USB adapter. Bad news because now 
access is limited to the functions available in the driver, usually far 
less than could be done with direct access to the UART, and the interrupts 
are now processed by the OS and are subject to excessive delays due to the 
poor design of the Windows event handlers.

I played around with writing drivers for NT and W2K for a while, but we 
finally went with external communications processors. We found that many 
low level serial protocols cannot work under Windows because the interrupt 
latency frequently exceeds the time outs required. I had better luck with 
Linux, but the bosses have decreed that MS Windows is the only OS that 
matters (for now).

Bob McConnell
N2SPP