USB to Serial Adapters

[daxtojeiro]

I have the later Prolific PL-2303X variant. There is a difference between the older PL-2303 chip which affects Linux users using the std kernel driver. Unfortunately the Product and Vendor IDs are the same for both chip versions, so depending on your Linux driver code it will report a successful load and attachment of the PL-2303. But when you come to use it it's useless.

I fixed this by upgrading Gentoo to the latest dev kernel - 2.6.9. I have seen some patches for 2.4, but I don't know if they work. Best to try the latest 2.4 kernel if you have the problem.

IIRC, the only way to deduce you have the X variant is to check the bMaxPacketSize0 and see if it gives 0x40 (64). Then you probably have one.

This cheap (£10GBP) device is working for me on both XP and Linux so far, but I haven't done any high throughput comms yet. I'll update if it fails at all.

Hope this helps. And here's my usbview output:-

Device Descriptor:
bcdUSB: 0x0110
bDeviceClass: 0x00
bDeviceSubClass: 0x00
bDeviceProtocol: 0x00
bMaxPacketSize0: 0x40 (64)
idVendor: 0x067B
idProduct: 0x2303
bcdDevice: 0x0300
iManufacturer: 0x01
iProduct: 0x02
iSerialNumber: 0x00
bNumConfigurations: 0x01

ConnectionStatus: DeviceConnected
Current Config Value: 0x01
Device Bus Speed: Full
Device Address: 0x01
Open Pipes: 3

Endpoint Descriptor:
bEndpointAddress: 0x81
Transfer Type: Interrupt
wMaxPacketSize: 0x000A (10)
bInterval: 0x01

Endpoint Descriptor:
bEndpointAddress: 0x00
Transfer Type: Control
wMaxPacketSize: 0x0507 (1287)
wInterval: 0x0202
bSyncAddress: 0x40

Endpoint Descriptor:
bEndpointAddress: 0x00
Transfer Type: Control
wMaxPacketSize: 0x0000 (0)
wInterval: 0x0000
bSyncAddress: 0x07

Errrm, and now in English please Im really struggling with this USB thing any drivers or anything I need can someone help please? It just keeps losing comms when in the front screen so I cant datalog or anything
Phil

[mbohn]

Here's something that is helping me cope with the wandering com port syndrome. (That's what happens when you change your usb connections frequently and the com port assigned to your MS becomes a pseudo-random number).

Put on your desktop a shortcut to the System folder. To do this go to control panel and locate "System." Right drag that to the desktop. This will save a few clicks down the road.

BEFORE you plug in your serial-usb connect to your computer open up the system folder, click the hardware tab, click Device Manager, then click on the "+" next to "Ports (COM & LPT). Note your Com ports, especially any that start with "Prolific USB..."

Now, plug in your serial-usb connector. In a couple of seconds the Device Manager screen will refresh. You'll need to click the "+" next to "Ports (COM & LPT) again but there will be a new entry giving the com port your serial-usb cable is using.

Now you can run MT and select this com port.

(Maybe someday MT will find the MS for you!)

[MegaScott]

Phil,
You have a new laptop so you are running Windows XP? You have gone onto the Prolific driver and fittled with the Com buffers? Experiment with different buffer sizes maybe. Also you say the mouse has an effect? try changing the Port number to a different one. Are you using a usb mouse as well? A ps2 mouse should be using IRQ 12, and your USB ports should be IRQ20-21.
I have one of these damn USB thingy's, and a serial analyzer, maybe I'll add USB troubleshooting to the list of stuff to do.

[daxtojeiro]

Hi Scott,
yes its a new laptop with a built in mouse, I dont think the mouse is actually having an effect now, although at times it feels like it is. I will check to see what driver Im using but Ive just ordered a pcmcia - rs232 converter card, I really hope this cures the problem, getting desperate now as summer is looming,
Phil

[milesinfront]

I'm not getrting any joy from an ATEN brand, Model UC-232A.

Also no joy with the Prolific brand adapter labeled ST Lab......

[efahl]

rickmilesracing wrote:
> I'm not getrting any joy from an ATEN brand, Model UC-232A.
>
> Also no joy with the Prolific brand adapter labeled ST Lab......

Rick,

Have you tried messing with the fifo buffer size in the driver settings,
like Brent mentioned on another thread? If you can find this stuff in
the settings, drop the buffer sizes as small as it will allow (10 bytes
or so) and see if that helps.

Have you modified the settings in the ini file that you are using? The
two values of interest are "writeBlocks" and "interWriteDelay."

Eric

--
Eric Fahlgren http://www.not2fast.com/



(posted by email)

[milesinfront]

I haven't messed with these settings yet! Which ini file is it? The FIFO adjustment on my XP machine is just a couple of sliders. I have already returned the ATEN to it's source, but I own the 'Horrific', opps, Prolific.....

I have a PCMCIA Serial card on order. Are these generally fool proof???

[daxtojeiro]

I haven't messed with these settings yet! Which ini file is it? The FIFO adjustment on my XP machine is just a couple of sliders. I have already returned the ATEN to it's source, but I own the 'Horrific', opps, Prolific.....

I have a PCMCIA Serial card on order. Are these generally fool proof???

Hi Ive messed with those settings and got no where with them, but Ive got a pcmcia card coming soon so I hope this cures the trouble, you could always use MegaTunix if not as that runs without issuse with USB, thats what Ive been doing on the laptop,
Phil

[milesinfront]

I have just installed my PCMCIA Serial card from Quatech!

I instantly found some new problems which I have mostly ironed out. I seem to be getting some Divide By errors. I will copy the full error if it returns.

Other than that I can say that the PCMCIA is a good solution for those with deep pockets.......

[milesinfront]

The error I get from MT on start up (MS connected and powered) is:-

'Error: divide by zero. '(nCyl2+1)/divider2

MS Code is 020i and MT 2.25b271