Film-Tech Forum ARCHIVE: PC USB-to-Serial adapters

This is topic PC USB-to-Serial adapters in forum Film-Yak at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=8;t=001650

Posted by Michael Schaffer (Member # 1204) on 01-16-2003, 06:20 PM:

I am thinking about buying a new notebook. Many attractive new ones come without the serial connector we all know is needed for such favourite tools as Dolby and SDDS setup programs. We have already widely discussed running those programs on a Mac under Virtual PC using such an adapter. I know that there are similar adapters available for PCs which plug into the USB port and have a serial connector on the other side. Is anybody familiar with them? Do they work for cinema applications such as hooking up the notebook to a Dolby or Sony processor?

Posted by Daryl C. W. O'Shea (Member # 1303) on 01-16-2003, 06:46 PM:

In theory you shouldn't have any problem with the USB <-> Serial adapter with applications that run under Windows 98 and later, like the SDDS software.

You'll probably have problems with software that runs under native DOS or a DOS4G / DOS4GW if you don't have a DOS device driver to 'make it happen'. [Smile]

If I can find my USB <-> Serial adapter I'll try it out. I think I left it up north though, so it'll be awhile.

Posted by Greg Mueller (Member # 17) on 01-16-2003, 07:43 PM:

These puppies can get expensive. I'm running Windoz XP on a laptop and had a real headache getting my adapter to work. Apprently XP is not real friendly to IO. The unit I bought was a pcmcia Ruggedized Dual IO Card by Socket Communications. It took sometime and a few phone calls (and one exchange) to get it to work. It works now but what a pain. They are constantly improving these things and I would imagine they've figured it out by now, but who knows. I should also mention that this same card apparently worked fine under Windoz 2K
The ones I hear are better than others are the Quatech DSU-100 and the EdgePort 421.
You can also get a variety of these adapters really cheap, but they have a variety of problems, and getting them to work them same way every time can be difficult

Posted by Daryl C. W. O'Shea (Member # 1303) on 01-16-2003, 07:46 PM:

Of course you can always go with a docking station, if the machine supports one, but that doesn't look so cool does it. [Smile]

Posted by Michael Schaffer (Member # 1204) on 01-16-2003, 10:49 PM:

XP doesn`t allow programs to directly access the hardware. SDDS setup does not work under XP. It runs, but it doesn`t communicate with the serial port. WinDRAS works under XP. It would be nice if such an adapter came with a driver that emulates direct hardware access for the programs and then passes the data on to the USB port. Then there should be no problems. I am not familiar with the signal structure on the USB port. Does anyone know if the conversion to serial data takes places in the adapter or if it is done by software?

Posted by Daryl C. W. O'Shea (Member # 1303) on 01-16-2003, 10:57 PM:

It's generally a software emulated serial port.

The software converts the serial data into a dataform compatible with the USB interface. The adapter itself converts the 'USB data' back into RS-232 compliant serial data. The same works in reverse.

Posted by Michael Schaffer (Member # 1204) on 01-17-2003, 10:45 AM:

Have you had an opportunity to try it with a DA20/500/650?

Posted by Daryl C. W. O'Shea (Member # 1303) on 01-17-2003, 12:14 PM:

No but if I can find the darn cable I'll try it out with a CP-500.

Normally I just use my Dell Inspiron that has a serial port but carrying around the lighter Latitude would be a lot nicer. [Smile]

Posted by Michael Schaffer (Member # 1204) on 06-09-2003, 10:25 PM:

I just tried it with a Toshiba notebook and an adapter from Belkin to a DA20. Of course, it didn`t work.
What can be done about that? I imagine a lot of you out there also have newer notebooks without a serial port, so what adapters are you using?

Posted by Daryl C. W. O'Shea (Member # 1303) on 06-10-2003, 01:23 AM:

The USB to Serial adapter that I have been using has an FTDI (Future Technology Devices Intl Ltd. - http://www.ftdichip.com/FTApp.htm) FT8U232 chipset. I've been using it with Windows 2000 but there's no reason why it wouldn't work the same under XP.

Anyway, WinDRAS locks up when it's used with the USB to Serial adapter but DRAS10 and Load500 work fine.

Here's a picture of the (gray / silver) cable hooked up.

Here's a blowup of the serial port end.

[ 06-10-2003, 03:44 PM: Message edited by: Daryl C. W. O'Shea ]

Posted by Michael Schaffer (Member # 1204) on 06-10-2003, 02:13 AM:

quote:
WinDRAS locks up when it's used with the USB to Serial adapter

That sounds very promising!
[Frown]

There doesn`t seem much that one can do except for trial-and-error testing of various adapters. Still, what is it that makes it so complicated for a variety of adapters to work? Under normal circumstances, the OS would hand the data to the serial port. I understand the adapter software emulates the port, but how can it be so difficult to make it work when the reversion from USB data back to serial data is a mirror process?
What could be won from playing with the COM port settings? If any, which would be the settings most likely to reach a solution (data rate, parity, stop bit etc)?

Posted by Richard Hamilton (Member # 321) on 06-10-2003, 08:26 AM:

Michael,
USB to Serial this shows a few tests. I have tried a Belkin F5U103 and it is a piece of junk. It is a little box that both cables plug into. It locked up my laptop when hooked to either a CP-650 or a Media Matrix. When I was in Canada last month, I found an adaptor that looks like the one that Daryl has, and it works fine with the equipment. There isn't a brand name on the cable, and the device comes up as a Prolific USB to Serial adaptor. Hope this helps,
Rick

Posted by Jason Burroughs (Member # 68) on 06-10-2003, 09:44 AM:

More ane more laptops are comming with out serial port on them as they are generally considered part of a "legacy" system. The USB-Serial adapters should work, in theory. However I haven not seen much success in getting them to actually work on true serial devices. About the only thing that I've seen work successfully on a USB-Serial adapter is a PDA.

I believe the problem lies in that is not true UART but emulated. Anything emulated never works as well as the real thing.

Posted by Randy Stankey (Member # 64) on 06-10-2003, 10:08 AM:

I have used a Keyspan USB/Serial adaptor to hook my iBook to several things: Dolby Digital (DRAS 10 & WinDRAS)... U.S.L.'s DSP-60... Sony SDDS... Sync-ing Palm Pilots.

Every one of them worked fine once I got the driver for the dongle installed properly and got the software that I am using to know where the drivers are located.

When I used this dongle for Dolby, I had to run DRAS under Virtual PC and that's where the beauty of the thing lies. The emulator takes care of handling the dongle and its drivers. The "guest" software doesn't even know that it isn't running on a real PC, nor does it even know that it isn't talking through a real serial port.

When run with an emulator like VPC, the guest OS and the guest application(s) run slower than they normally would but when you're talking about doing the kinds of things we do, speed isn't critical as long as the thing is fast enough to get the software to run.

Now, even when NOT running under VPC and using Mac OS 9 or OS X I have not had very many troubles with the thing once I got it set up in the first place. The only thing I ever had happen was under OS 9. When I accessed the modem, the OS would switch the I/O stream away from the Keyspan adaptor and to the modem port. When I wanted to use the adaptor I would have to remember to put it back. Once I got updated to OS X this ceased to be a problem. OS X just "knows" what to do with the adaptor. When you plug the thing in, the Kernel Extension(s) for the thing load automatically. When you unplug the thing, the KEXTs unload. It seems to happen auto-magically! (Unless you listen for the sound of the HD when the software loads. [Wink]

)

I know that Win-95 (via VPC), DOS 6.6 (via VPC), OS 9 and OS X handle it well on the Mac. As to how other computers or OS-es handle the Keyspan (or other brands of) adaptors I can't attest.

Posted by Daryl C. W. O'Shea (Member # 1303) on 06-10-2003, 04:08 PM:

The FTDI chipset based adapters are actual hardware UART chips. Probably why they seem to work 'better' than other adapters.

Hmmm... maybe you could run the Dolby software under Virtual PC under BasiliskII on your PC. [Smile]

Mike, try running DRAS10 and Load500 using the adapter you have. I haven't had time to play with settings to get WinDRAS to work... if I do I'll let you know.

If anybody wants one of the cables I have, I could mail you one. They cost about $80 CDN.

Posted by Michael Schaffer (Member # 1204) on 06-10-2003, 06:05 PM:

I will try that, but I have no hope that it will work - DRAS10 is a DOS application and I know from other unhappy experiments (SDDS setup) that XP does not allow any programs to directly access the hardware. And that is exactly what DRAS10 wants to do. I will also try it with a parallel installation of 98.

Posted by Randy Stankey (Member # 64) on 06-10-2003, 06:24 PM:

I always ran DRAS from within Virtual PC but I think the concept will transfer.

I found that I got much better results from DRAS if I made a DOS virtual machine and ran DRAS10 rather than installing Windoze and running WinDRAS.

Thus, I speculate whether DRAS would work better if you made a DOS partition on your computer and stuck with that. My only question would be whether the driver(s) for the dongle can be made to work through DOS. Again, when running DOS & DRAS through an emulator I don't have to worry about it. The emulator also makes the dongle emulate the serial port(s) that DRAS wants to see.

Posted by Michael Schaffer (Member # 1204) on 06-11-2003, 01:45 AM:

I also ran SDDS setup on a Powerbook with Virtual PC (Windows 98) and an adapter and it worked very well.
I forgot to try if WinDRAS or DRAS10 will work under XP in one of the compatibility modes.
I can't spend all my time playing with USB adapters though. Does anyone know if the compatibility modes allow applications direct hardware access (at least in theory...)?

Posted by Daryl C. W. O'Shea (Member # 1303) on 06-11-2003, 02:08 AM:

NO! Direct hardware access just isn't allowed under NT, no matter what.

DRAS10 doesn't need to directly access the hardware when using the USB adapter, the adapter's driver answers calls made to the regular COM port and routes them through the USB device.

DRAS10 won't normally work under Windows 2000 either, but it will when using a USB device (that also works properly).

Posted by Michael Schaffer (Member # 1204) on 06-11-2003, 02:38 AM:

Well, I just tried it - DRAS10, but it didn`t work ("cannot establish communications with serial port").
I don`t quite understand what you wrote: The adapter`s driver will answer calls to the COM port, so the driver has to hook into the communication between the program and the OS which would normally route the calls to the COM port?
In that case, maybe the communication between the adapter and the DA20 might still not work, but shouldn`t the program think it communicates at least with the serial port? In other words, doesn`t the error message I got contradict this?
Or maybe the answer is already in your post: if the device works properly... [Frown]

Posted by Daryl C. W. O'Shea (Member # 1303) on 06-11-2003, 03:31 AM:

I think you understood what I wrote. Good thing, cause I think I'm halfway to confusing myself. [Smile]

Normally when an application (app) asks for access to a COM port (instead of the COM driver which app's are now supposed to do) the OS says, no [fu]

Actually, it just completely ignores the request, basically telling the app that the hardware doesn't exist.

The driver for the USB to Serial adapter I have seems to act as the actual COM hardware that old app is asking for. So the app gets a response and it's happy.

I don't even have any special settings, in fact I never changed the defaults on anything.

In the Device Manager:

COM1,9600,8,N,1,N

or COM Port 1, 9600 bits per second, 8 data bits, parity none, 1 stop bit, flow control none.

Recieve and Transmit buffers are also set to high (14 and 16).
I'm also using the defaults in both Load500 and DRAS10.

If you're using the same, I'd say that the adapter or driver you have just doesn't work.

Did you try it out with Win98?

Posted by Michael Schaffer (Member # 1204) on 06-11-2003, 03:11 PM:

No, not yet, but I just got a response from Belkin support, which confirms your analysis: "in some cases, the software is unable to communicate with the virtual COM port."
The software here means the program I want to run. Of course, I have a simplistic view of the processes involved, but I can not understand why some programs would find it more difficult to communicate with the emulated serial port than others. What is so complex about this exchange that some programs refuse to talk to the virtual COM port?

Posted by Daryl C. W. O'Shea (Member # 1303) on 06-11-2003, 03:36 PM:

That's just a lame excuse for a product that doesn't work as good as it could. It sounds like their driver (and probably hardware too) isn't capable of precisely replicating a traditional COM port.

If that's the case then I doubt it'll work under Win98 either... unless of course the person who wrote the Win98 driver was able to make it work correctly.

Posted by Michael Schaffer (Member # 1204) on 08-28-2003, 01:04 AM:

Yeeeeeeeeeeeeeeeeeeeeeeeeees!
The Keyspan USA-19QW works great with my Toshiba notebook running Windows XP and a variety of cinema hardware and programs. What a relief! Now I can stop dragging the second "legacy" notebook around with me.
It also has a cool software which allows you to test and config the emulated serial ports.