testing com ports

  hko 20:17 12 Jan 2005
Locked

I need to check that my comports are working fully. Both RS232 and printer 25 way D.

to check that lines are switching correctly, I would like to put a meter on each line in turn by using 1mm plugs/sockets and then use the keyboard to shange the level of the line. Is this possible?

Many thanks

HKO

  octal 21:29 12 Jan 2005

Unfortunately you can't just use a meter to measure to serial or parallel ports.

You are able to view the data using an oscilloscope, but the picture will show lots of square waves on the screen of the scope all with varying mark/space ratio depending on the data being sent, which is totally meaningless. Some of the pins on the parallel port are either high +5 volts or low 0 volts, depending on the instruction being sent to the peripheral device.

Is there some reason why you need to measure it?

  octal 21:43 12 Jan 2005

This may be of interest for the parallel port, scroll down the page for Parallel Port Viewer (Java) FreeWare click here

I've never tried this program, so you'll have to have a go yourself. I can't find a similar program for the serial port at the moment.

  octal 22:12 12 Jan 2005

This is an oscilloscope view of a serial port using a clock to synchronise the data.

click here

As you see its not a simple matter of using a meter. sorry, its probably not what you wanted to hear, but you can see the problem of measuring these things.

  hko 19:33 13 Jan 2005

Thanks Octal, I am trying to control my transceiver using a level shifter via the printer port.
I have had the system working a couple of years ago but not at present. I worked on it today and got results between an old laptop and the computer but it is a complex process of getting everything to agree. I suspect that for some reason the ports are not set set up on the PC. I have now found out that there is no lpt1 set up. Of course I am using USB for the usual perifs. I now have to find out how to re setup the coms ports. I will have a look at the parallel port program ato see if that helps.

Thanks again.

By the way the serial port is used for keying the transmitter for cw. That is playing up as well.

I'll strick at it

best wishes

hko

  hko 19:33 13 Jan 2005

Thanks Octal, I am trying to control my transceiver using a level shifter via the printer port.
I have had the system working a couple of years ago but not at present. I worked on it today and got results between an old laptop and the computer but it is a complex process of getting everything to agree. I suspect that for some reason the ports are not set set up on the PC. I have now found out that there is no lpt1 set up. Of course I am using USB for the usual perifs. I now have to find out how to re setup the coms ports. I will have a look at the parallel port program ato see if that helps.

Thanks again.

By the way the serial port is used for keying the transmitter for cw. That is playing up as well.

I'll strick at it

best wishes

hko

  octal 19:50 13 Jan 2005

Oh, I understand!

__... ...__

G4LNA :-)

  octal 19:51 13 Jan 2005

Oops, trying to be cleaver and send 73 but the forum defeated me.

  octal 19:54 13 Jan 2005

By the way, don't you have an oscilloscope to help?

This thread is now locked and can not be replied to.

Elsewhere on IDG sites

AMD Radeon Adrenalin release date, new features, compatible graphics cards

Inside the iMac Pro - Apple's most powerful Mac yet

iMac Pro release date, UK price & specs

Comment nettoyer Windows et optimiser son PC gratuitement ?