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Billy T
27-03-2013, 10:07 AM
Hi Team

Has anybody successfully used USB to serial adapters to communicate with legacy (DOS only) devices?

In the past I've had to go into bios to configure the port parameters to get my instruments operating and I can't see that those options would be available on an adapter, but I live in hope. I maintain an elderly W2K system, which was the last usable iteration I've had, but I need on-site access via a laptop from time to time and my geriatric Libretto 50CT seems to be at the end of its life.

Cheers

Billy 8-{)

Chilling_Silence
27-03-2013, 10:50 AM
Yes some of the cheaper $30 ones from PBTech worked well for an old device I was using back in the day, but it took a fair bit of fiddling :p

Agent_24
27-03-2013, 11:07 AM
Never tried one myself, I suppose you could just 'suck it and see'

I've heard the USB to Parallel ones are useless for anything other than printers, but haven't tried one of those either.

Alex B
27-03-2013, 11:10 AM
USB to Centronix seems to work OK, if that's what you mean for printers.

Yes the USB to RS232 can be a real PITA, getting harder to find decent laptops with build in serial too.

Agent_24
27-03-2013, 11:18 AM
USB to Centronix seems to work OK, if that's what you mean for printers.

Yes, although Parallel Port\Interface or IEEE 1284 is probably more accurate. Centronics is the name of the company.

The connector is typically a DB-25 or a 36-Pin "Micro Ribbon" http://en.wikipedia.org/wiki/Micro_ribbon

MushHead
27-03-2013, 01:15 PM
We've had varying levels of success over the years with these; ever since "real" serial ports started disappearing, we've had issues with techs being able to access our old equipment, some of which required RS485 access via an adapter. It came down to the quality of the drivers a lot at first, especially when you need real-time control of the RTS line to switch the RS485 transceiver between receive & transmit modes. We originally standardised on the Dick Smith adapters, since they were reasonably readily available on short notice & they worked pretty well, plus the design stayed constant (the current ones HERE (http://www.dicksmith.co.nz/product/XH8290/dse-serial-usb-adaptor) still seem the same now as they did years ago).

It comes down to what you're trying to do with them. Standard RS232 is usually pretty straightforward (we have the cheapo Digitus ones working happily in most applications also), but running DOS programs from a W2K command prompt causes lots of issues; if that's what you're doing I'd have a look at DOSbox as an option - I use it for a couple of legacy apps that I've been using from W2K to XP to W7x64 with no issues).

Billy T
27-03-2013, 04:10 PM
It comes down to what you're trying to do with them. Standard RS232 is usually pretty straightforward (we have the cheapo Digitus ones working happily in most applications also), but running DOS programs from a W2K command prompt causes lots of issues; if that's what you're doing I'd have a look at DOSbox as an option - I use it for a couple of legacy apps that I've been using from W2K to XP to W7x64 with no issues).

Yes 'cough' well, I have been running with W2K on my old machine and on my old laptop, plus W95 on my Libretto and the laptop has been problematic, while the Libretto went awol some time back. It was the idea of buying a second-hand Libretto without serial port that got me thinking about port convertors. I was going to ask about DOSbox too, because some port configuration is required. My problem is that the handshake is not taking place so I can't initiate a download of data.

I also considered running DOS 6.22 (at least I think that is tet version that I have, in a virtual machine and fortunately I have a USB floppy disk) plus I have an unused copy of MS Virtual PC to run it on. Computer Lounge looked at me sideways when I specified a serial port on my current machine, but some companies haven't caught up with the World of today and as needs must, I had the port installed. They don't know about Y2K either, so I'm perpetually tied to the last century!

Cheers

Billy 8-{)

MushHead
27-03-2013, 08:38 PM
One of the adapters we got at one point (this must have been 5+ years ago) was good enough to work out what the DOS program was trying to do with its direct port access & emulated a 16C550 so well it worked in a DOS command prompt with no fiddling around at all. Unfortunately, as is the way with these "niche" products, the supplies disappeared as soon as we noticed that the driver was a cut above the rest. DOSbox should do the trick for most things, assuming you're using a DOS program for access (?); just need to set up the port access info in the configuration file & you should be good to go.

gary67
28-03-2013, 07:19 AM
If you do get one make sure its got the Prolific chip the cheap ones usually don't. I don't use them for DOS but do use them for my garmin Etrex. Unfortunately I sold my last spare one to Karamea Dave. I parallel imported a few from Aliexpress cost about $25 each NZ

paulw
28-03-2013, 08:41 AM
We've found with these things over the years it's a bit of a turkey shoot to find one that works. The DSE ones never work on most of our legacy PBX systems..

Cellux
28-03-2013, 02:02 PM
Yes the USB to RS232 can be a real PITA, getting harder to find decent laptops with build in serial too.

Some of the new HP Elitebooks still have them, which is super handy.