OT: USB to RS232 converter?

Can you really slow down a USB port to 9600 baud and then just a USB to 9 pin D connectors and cable to connect from a modern netbook PC to exercise an an ancient bit of kit with some HEX function codes. Suitable driver for such purpose ?

Reply to
N_Cook
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"N_Cook" schreef in bericht news:k519pm$2d4$ snipped-for-privacy@dont-email.me...

Well, a software implementation of USB *does* excist but on a powerfull micro where it has highest priority leaving the processor little time for other tasks. The modern netbook has a very powerfull processor but that processor is interrupted by the OS too often to play software USB.

petrus bitbyter

Reply to
petrus bitbyter

There are inexpensive adapters, such as the ones made by Plugable. They will generally work when you are directly addressing the RS-232 hardware.

Reply to
William Sommerwerck

will

Or the other similar I was looking at has active chipset conversion in the adapter, but always seems to refer to fast serial links useage, I've not seen specifically as low as 9600. And whether Prolific or FTDI chipsets, seems to be horses for courses, and reading around this topic a number of people seem to end up with the wrong horse. If it was possible to slow down the USB then just wasted some driver download time if no connection emerges

Reply to
N_Cook

$1.85 US for the interface & software. Then use Hyperterm, or other terminal program. The converter is seen as a real com port. What's your time worth to screw around and try to cobble something up?

Reply to
Michael A. Terrell

The problem is that Prolific (Tiawan) is the second largest manufacturer of bridge chips. Prolific writes the official Windows drivers for their chips, which manufacturers of adapters using them provide to their customers.

The largest manufacturer of bridge chips is an unnamed (at least to us in the west) mainland Chinese company which makes almost compatible Prolific copies.

Prolific found this out and exploited a difference in their chips from the copies and their drivers no longer support the copies.

So if you are using Windows XP or VISTA, you can use the official Prolific drivers with both real Prolific chips and the copies.

If you are using Windows 7 or Windows 8, it will automaticaly use the latest drivers which will not work with the copies. If you manually install an older version which does work, Windows update will automatically replace it with one that does not. You have to turn off automatic updates for that driver to continue to use those chips.

The Linux drivers, written only with the published specs work fine with both. I believe that is also the case with MacOs, but don't hold me to it.

The Chinese vendors of cables that use the Prolific copies are now listing them on eBay as Windows 98/ME/2000/XP, leaving off VISTA, 7 and 8.

Geoff.

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Geoffrey S. Mendelson,  N3OWJ/4X1GM/KBUH7245/KBUW5379 
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Reply to
Geoffrey S. Mendelson

USB is nothing like RS-232. The only thing they have in common is that they are serial protocols.

Both Prolific or FTDI chipsets will do 9600 baud. I've used both at that speed.

The Prolific 2303 goes down to 75 Baud. The driver allows you to configure the converter like any other RS-232 port.

12000000 6000000 3000000 2457600 1228800 921600 806400 614400 460800 403200 268800 256000 230400 201600 161280 134400 128000 115200 57600 56000 38400 28800 19200 14400 9600 7200 4800 3600 1800 2400 1200 600 300 150 110 75

FTDI:

formatting link

Reply to
Michael A. Terrell

No. For a lot of reasons, but for one big one, the USB protocol requires a master and a slave (one at each end of the wire) which exchange status pretty much all the time. The slave cannot send a message until the master gives permission. Completely unlike a "standard" serial port.

As others have mentioned, the way to do it is with a USB-to-serial converter -- the not-USB side of those really does behave just like a serial port.

But be careful: some adapters include RS-232 line drivers and receivers, and some do not, and many times the specs will be unclear at best. RS-232 drivers and receivers are inverting devices, so even with 5 volt signal levels all around (quite common), the inversion means that a port of one sort cannot talk to a port of the other. I have seen complete adapter cables, USB at one end, DB-9 at the other, but with the wrong polarity of signals in the DB-9 so it cannot work with a "standard" port. If both ends use RS-232 polarity, or what is called "TTL" polarity, things will probably be fine.

Whatever one you get will probably require a device-specific driver, though some OSes have some drivers already installed.

Isaac

Reply to
isw

9

exercise

Will go for adapter cable supplier that specifically states Windows 7 OS and slow serial speed options , and try and find the remaining specs you mention in their blurb

Reply to
N_Cook

If you have a desk top, you may want to invest in a real RS-232 card or look at the spec's on your mother board. it's very possible you already have one on the board but need to get a cable and back plane to bring it out to the back and then of course, turn it on via bios.

Jamie

Reply to
Jamie

There's another issue that hasn't been addressed.

The RS-232 interface is obsolete. Any device using it is a "legacy" device. The drivers are 16-bit or 32-bit, because the manufacturers don't care to spend money to update their products. Just because a Plugable or other major brand of USB-to-serial adapter can be successfully installed on a 64-bit system, doesn't mean the driver will work.

These adapters work best when the program was written to directly address the serial interface hardware, without a driver.

Reply to
William Sommerwerck

to

requires

status

receivers,

volt

port

and

mention

I have current TIA-232, 422, 423, 485, 530, 561, 562 standards. I use them to sort out various things in the workplace. After proving access in the workplace a few times coworkers have quit arguing with what i say the standards do or do not say. Not all product comply with the standards. Most frequently, vendors hot rod "232" interfaces far beyond the 20,000 baud limit in 1.8.3 of TIA-232.

?-)

Reply to
josephkk

device.

to

major

address

Not with USB to 232 adapters. At the user level it looks the same but the OS hides many details. Userland applications do not see hardware any more, just an abstraction (if you are very lucky, a virtualization) of it. Industrial ISA based computers are a different case.

?-)

Reply to
josephkk

This old kit works well with "macros" via Hyperterminal to 25 pin RS-232 and Win98 but it has to go out on the road so control via a netbook pc would be ideal. In the meantime of getting a USB to RS232, tried porting win98 hyperterminal to Windows 7 just to see if it will at least open on that OS but bugger me 7 OS/ Explorer hides DLL files and cannot copy/paste the hyperterminal .dll from thumbstick

Reply to
N_Cook

and

be

you can't change .dll to .txt or something , to copy across either

Reply to
N_Cook

device.

Then explain why I couldn't get any of the three devices (a Wacom graphics tablet, a Dymo thermal printer, and a Brother label maker) to work. They're for sale -- and not at giveaway prices -- to anyone who thinks he can get them to work with a Plugable or Tripplite adapter.

Virtually every program Plugable recommends their adapter as suitable for uses direct hardware access.

Plugable accepted return of the adapters without argument. It made no attempt to help me resolve the problem. I interpret this not as laziness or irresponsibility, but an acknowledgement that there was nothing they could do.

The problem seems to be that these devices use 32-bit drivers -- and 32-bit drivers won't work under Windows 7 64-bit. This is principally because they handle data variables and addressing differently, and Microsoft can't or won't provide a thunking layer (as it does for applications).

Microsoft has a Web article on converting 32-bit drivers to 64 bit. The process doesn't look horribly difficult (the compiler locates most (if not all) of the incompatibilities), but it isn't simple or obvious.

For me, the issue is moot, because after too many hours of experimentation, I gave up. I bit the bullet and bought newer USB products.

Reply to
William Sommerwerck

Anyone any idea where there is a live download site, ie not dead links/ google adword junksites, to this hyperterminal version?

htpe63.exe

Reply to
N_Cook

Reply to
Michael A. Terrell

Teraterm is another freeware terminal program. V4.75 was released

2012-08-31 17:30. it is halfway down this page:

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Reply to
Michael A. Terrell

I will try the win7 compatible one mentioned there. when I get back to it, currently inundated with a plague of repairs involving blown mains fuses, perhaps there was mains surges locally

Reply to
N_Cook

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