PC pat cable

[Monkeh]

All I have is usb and a little D shaped female for a monitor, I think, and a ethernet socket.

Wow, that's bare.

what I don't get is if serial is old hat why cant the new sheriff in town do the same job as the old bloke

Oh, it can. The problem is it's more expensive to implement. USB is a very complex (and by some, much hated, with reason at times) interface, RS232 is very, very simple.

 

[Monkeh]

The PL-2303 never claims to adhere to RS232, merely to provide an RS232-like interface

Right, so most, if not all PL2303 cables have an additional device to provide the level change.

Some do, some don't, it's pot luck. I spent £10 on a cable and it has no charge pump, I spent £1.50 on a Taiwanese site, waited two weeks, and got one with a charge pump. The expensive one is good for RS232-like devices working at 5V (fairly rare kit unfortunately), at least..

Ok, well I stand by part of my original point that the driver works well and is otherwise reliable - never had any software related issues with the PL2303.

I've had major issues with it on Windows, especially if you use a 64-bit version of Vista or 7. Thankfully, Windows is little more than a toy, and I have more reliable systems to use my PL-2303s with.

It seems that it's down to the particular manufacturer of the cable as to whether all the lines are connected and at the right levels - so it's a lottery and picking a PL2303 based cable is no guarantee that it will work well electrically.

Correct. Reviews and recommendations are all you can go on.

 

[slup]

Well, this isn't really a review or a recommendation - but for our purposes CPC part number CS14522 has worked fine on every device we've used it with.

The thing is, these were bought about five months ago and there isn't even any guarantee that the ones they are selling now are the same!

I have spare one at the office - I'll stick a meter on it tomorrow and see what the levels are like.

 

[Monkeh]

Likely ±9V or thereabouts.

 

[maguire]

So I need a PL2303 , with a charge pump ?

 

[Monkeh]

So I need a PL2303 , with a charge pump ?

Yeah, but those terms won't get you anywhere trying to find one unless you want to build it yourself.

See the link I posted earlier, it should suffice.

 

[plugwash]

The problem with USB to serial cables is voltage. Most devices will operate at 12V (or 10V, which is close enough). USB is 5V, this is all that is available to the adapter. A charge pump is required, and not all devices are fitted with them.

Thats one problem, at least it's avoidable with a decent adaptor though.

Another problem with USB-serial adaptors is that they add a lot of extra delay to the serial signals. Depending on the communications protocol the device uses this can cause a major performance reduction or even stop the interface working entirely.

 

[maguire]

tried the one from trendnet no use, seaward directed me to these guys http://www.easysync-ltd.com/index.php will post the outcome at leat they are in Glasgow so I can always kick down a few doors if it dont work

 

[Monkeh]

Stick a meter on it, see what the signal level is.

 

[maguire]

I would not have a clue how to do that I know a AV guy would he know the test
Devlin

 

[Monkeh]

I would not have a clue how to do that I know a AV guy would he know the test
Devlin

Probably not.

The connector will have two rows of pins, one of four, one of five. Orient it so the five pin row is on top. Place one probe on the center pin on that row, and the other on the far right pin on that row. Read voltage.

 

[maltaron]

I picked up a little USB to serial dongle at a market stall in Whitehaven, it came with a driver disc and works fine. You do, however, have check which com port it is on.

 

[maltaron]

to follow up. search "USB to Serial" on E-Bay

 

[Monkeh]

to follow up. search "USB to Serial" on E-Bay

And probably get a cheap one which doesn't work.

 

[ban-all-sheds]

Or a cheap one which does - it might be worth a punt if it's cheap enough.

Let's not lose perspective here - this is a PAT downloading some data, not a disk drive. As long as the data doesn't get corrupted, then does it matter if it's a bit slow?