Film-Tech Forum ARCHIVE: USB to Serial adaptors

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Posted by Martin McCaffery (Member # 37) on 05-18-2014, 08:31 PM:

As most of our electronic equipment uses RS 232 to communicate, I'm thinking of getting a cheap Windows PC to use with them (we're a mac office, so this is newish for me).
From what I can tell, Serial ports are no longer on new laptops. I've done a little reading on USB to Serial adaptors and they don't seem to be satisfactory; and don't seem to be compatible with Win8.
Anyone have any experience or advice?

Posted by Justin Hamaker (Member # 2165) on 05-18-2014, 08:49 PM:

I have had mixed results getting these to work. But it's often more about finding drivers for the device that will work with Windows 7 or Windows 8.

It's not always as easy as putting an adapter between the device and the computer. Sometimes you will need to configure a Comm port which uses the USB. One device where I recently had success with this was an Epson TM-T88III receipt printer on a Windows 7 machine. Fortunately there are drivers available for Windows 7.

Posted by Jim Cassedy (Member # 4115) on 05-18-2014, 09:56 PM:

I've used a bunch of these devices to interface both ticket printers and
LED signboards that only had RS-232 interfaces.

The first one I bought cost around $25.00 and was sold under the "Gigaware" name
from Radio Shack. Had some problems with that one, but eventually got it
to work. "Just for fun" I bought a cheap one ($6.00) on e-bay and it worked
much better than the Radio Shack one. No problems! Worked so well that I
bought about half-a-dozen of them to use at several different theatres and
have not had a problem with any of them. One of them is driving an RS-232 line
that's over 50ft long. Both the Radio Shack & the "cheap" ones I bought on e-bay
seem to use the same chipset, but apparantly the ones I got on e-bay came with
better driver software.

All of them were pretty much "plug & play", except in two cases where all I had
to do was go into the computer's "device manager" and assign it a specific com
port, since the 'default' port the software wanted to use was already in
use by another device on those machines.

But, as Justin pointed out- - read the 'fine print' before you buy and make
sure the device you're buying comes with a driver that can handle the software
in the computer your'e using. (also make note if you need 32 or 64 bit)
For example, the driver for the Gigiaware/Radio Shack converter won't handle Win 8.

Posted by Chris Slycord (Member # 4239) on 05-18-2014, 10:09 PM:

quote: Justin Hamaker
I have had mixed results getting these to work. But it's often more about finding drivers for the device that will work with Windows 7 or Windows 8.

Is it a PITA to do XP in a VM for those situations?

Posted by Paul Mayer (Member # 355) on 05-18-2014, 10:36 PM:

I was lucky - the XP laptops I had at Strong and Callahan both had serial ports, so didn't need an adapter. My second much newer laptop at Callahan was Win7 and didn't have a serial port. I was going to go with the Christie-recommended Radio Shack adapter but it had just been discontinued. Office Max had the same adapter under a different brand name (about $45 in 2013), but I left that job before figuring out how to get things configured on the newer laptop.

Posted by Marcel Birgelen (Member # 6801) on 05-18-2014, 10:54 PM:

quote: Chris Slycord
Is it a PITA to do XP in a VM for those situations?

The VM can't access anything that the hypervisor can't. To be able to communicate with the converter, your host OS needs a driver. Once it's RS232, you can pass it trough via VMWare to your guest.

For some reason, putting a RS232 port on a notebook is too much to ask those days, even if tons of equipment out there is still using it. The biggest problem I have with those USB<->RS232 converters is indeed drivers and after that, figuring out on which virtual COM port they have installed themselves...

Posted by Jack Ondracek (Member # 1466) on 05-18-2014, 10:57 PM:

I've been using USB to serial converters for a long time. One of the radio automation systems I service uses them. In one case, I have 4 converters plugged into the same computer, with no problems.

These things are not rocket science. You can get them from Staples for about $35. Once installed, the assigned com port should appear on the software you want to use it on.

Of course, there are more exotic boxes out there. Quatech puts multi-port converters in boxes that look something like Netgear switches (the metal ones). They also work well, but cost more per-port and I don't see any real difference between them and a common office-store version.

Posted by Bobby Henderson (Member # 840) on 05-19-2014, 01:16 AM:

Our company has been using USB to Serial converters for quite a few years on getting certain types of LED-based electronic variable message center radios to link the host computer with the LED display. I haven't run into any problems with Windows 7 based PCs, but haven't had to deal with any Windows 8 based setups just yet. It's only a matter of time though. There's a lot of these LED displays out in the field. Old host computers eventually die and have to be replaced.

Thankfully the newest "jumbotron" systems have been transitioning away from RS-232 style communication and going to wireless Ethernet.

quote: Martin McCaffery
From what I can tell, Serial ports are no longer on new laptops.

9-pin serial ports disappeared from most laptop product lines during the middle of last decade. Not long after that they disappeared from most desktop computer lines. Even other port types, like Firewire, have been dropping by the wayside -at least on the PC side of things.

Posted by Marcel Birgelen (Member # 6801) on 05-19-2014, 01:48 AM:

The simplicity and reliability of RS232 is still mostly unbeaten. I would love to have a dedicated RS232 port on my notebook, but besides some rugged monstrosities, nobody is building them anymore.

Regarding this mess of "legacy" ports... Besides most DV and other semi-professional video equipment, Firewire was only really supported by two vendors: Sony, calling it iLink for whatever reason and Apple. It was only useful in the time frame between USB 1.x and USB 2.0. Features like direct memory access are now considered a security nightmare and I'm actually glad it almost completely went away.

Personally, I'm hoping that USB 4.0 will be around rather quickly and will kill the Thunderbolt nonsense of Apple (and Intel). USB 4.0 will finally even have the capability to replace the mess that currently is HDMI v.s. DisplayPort. Also, it promises to be backward compatible with all previous USB standards, at least on the protocol level.

Imagine: One type of port to connect ALL your peripherals. Sounds like a dream, doesn't it..?

The next step would be to harmonize all those wireless standards: WiFi, Bluetooth a whole bunch of proprietary implementations and maybe even wireless USB 4.0, all clogging up those few little bands of "unlicensed" spectrum.

Posted by Danial Simmonds (Member # 4638) on 05-19-2014, 03:40 AM:

Try ATEN USB to RS232 they are reliable been using it for years it can communicate without issues until today.

Posted by Carsten Kurz (Member # 5396) on 05-19-2014, 06:45 AM:

Keyspan are quite solid. If your're lucky, you could even get these to work in a virtual WIN machine running on a Mac.

They are now sold by Tripp-Lite.

They do work under WIN8.

Honestly, if you need this machine only for servicing, etc., I would try to get an older Dell XP or WIN7 laptop with a real RS232 port. They are still available for little money. Dell could even sell a few models with real RS232 ports.

Wether a USB-Serial works is highly dependent on the specific device and software. Sometimes the cheapest converter will work, sometimes USB-Serials will never work, because cheapo software uses e.g. handshake lines to create some strange protocol which is not a common serial protocol. Sometimes voltage levels are also a problem.

- Carsten

Posted by Stephen Furley (Member # 1277) on 05-19-2014, 06:54 AM:

Would have to agree with the ATEN one; with up to date drivers I haven't had anything that it didn't work with. It's a rather dull greyish/yellowish/brownish colour. There's what seems to be a very similar shape copy of it which is a more attractive blue colour, made by somebody else, and I've had problems using that with some devices, particularly under Windows 7.

The genuine ATEN one is available from Amazon.

Posted by Chris Slycord (Member # 4239) on 05-19-2014, 06:58 AM:

quote: Marcel Birgelen
The VM can't access anything that the hypervisor can't. To be able to communicate with the converter, your host OS needs a driver. Once it's RS232, you can pass it trough via VMWare to your guest.

I wasn't aware. I assumed it could passthrough direct control of the device, without having a driver for it. My bad.

Posted by Dave Macaulay (Member # 813) on 05-19-2014, 07:46 AM:

The Dolby CP650 is the unit I have had no luck with using a no-name adapter that worked with Barco projectors and a Jnior. I just got a Keyspan adapter (recommended by someone at Dolby) but haven't been near a CP650 yet to try it.

Posted by Carsten Kurz (Member # 5396) on 05-19-2014, 08:57 AM:

quote: Chris Slycord
I wasn't aware. I assumed it could passthrough direct control of the device, without having a driver for it. My bad.

Actually, both is possible, depending on the implementation. e.g. under OS X, you could have a native supported USB-Serial adaptor which establishes serial ports for OS X. These ports could be forwarded to a VM running windows as COM-Ports. But you could as well forward the Mac USB-Ports to the VM and install windows drivers for the USB serial. One or the other variant could work or not, depending on VM software, driver robustness, USB adressing scheme, etc.

- Carsten

Posted by Steve Guttag (Member # 268) on 05-19-2014, 10:44 AM:

For the older laptops that had a PCMCIA slot, I used SocketCom's serial adapter. That was the best...it was every bit as good as a hard serial port.

For my current Win 7 machine(Thinkpad W520), I'm using Brain Box's serial adapter, which is also a hardware solution and also works on most everything but a JSD80. So, far, even using the Keyspan USB adapter hasn't been able to connect to a JSD80 serial only processor. Win 7 on a JSD80 Ethernet processor hasn't been an issue though.

One of these days, I'll figure out the right combination of device/drivers to get the JSD80 to work well enough. We don't have many to contend with and most were updated for DCinema to Ethernet. Another possibility, I guess is to get an Ethernet to RS232 adapter, like Lantronix and just turn the JSD80 into an Ethernet device.

On the CP650, everything I've tried has worked...including the Keyspan adapter on Win 7 or Win XP.

Posted by Dave Macaulay (Member # 813) on 05-20-2014, 07:43 PM:

If there's no luck with the Keyspan I can get a "CE" serial card that should be basically a hardware serial port on the PCI bus. I don't have any experience with these cards though, like are they hot-pluggable.

Posted by Chris Slycord (Member # 4239) on 05-20-2014, 11:55 PM:

quote: Carsten Kurz
Actually, both is possible, depending on the implementation. e.g. under OS X, you could have a native supported USB-Serial adaptor which establishes serial ports for OS X. These ports could be forwarded to a VM running windows as COM-Ports. But you could as well forward the Mac USB-Ports to the VM and install windows drivers for the USB serial. One or the other variant could work or not, depending on VM software, driver robustness, USB adressing scheme, etc.

Virtualbox on linux definitely works like this. And I believe also when using vmware.

Posted by Marcel Birgelen (Member # 6801) on 05-27-2014, 03:30 AM:

quote: Carsten Kurz
Actually, both is possible, depending on the implementation. e.g. under OS X, you could have a native supported USB-Serial adaptor which establishes serial ports for OS X. These ports could be forwarded to a VM running windows as COM-Ports. But you could as well forward the Mac USB-Ports to the VM and install windows drivers for the USB serial. One or the other variant could work or not, depending on VM software, driver robustness, USB adressing scheme, etc.

VMWare also supports "hardware bypasses", I've used it a few times for stuff like USB dongles containing license keys. It is, however, very flaky and I've never seen it working with an USB/Serial convertor. The primary problem is that USB doesn't have a fixed addressing scheme, you have to identify USB devices by other means, like their hardware IDs.