Serial port problem

[Squintz]

I'm really confused. I have a Zektor HDS4.2 A/V Matrix. I also just built a Mini ITX PC running Windows XP Pro. When I could not get the Zektor to talk to CQC I assumed I had a cross over cable when it should be a straight though. In fact when I ohmed out the cable I confirmed that was indeed the case. So I went and built my own cable and ohmed it out to make sure it was all good. I connected that cable and CQC still could not connect.

So I started thinking that maybe the CQC driver was the issue. I looked up the protocol and opened up HyperTerminal and tried to send commands. NOTHING WORKED.

I then figured I must have a bad serial port. So I used my laptop (different computer) to connect directly to the Zektor via a USB to Serial adapter. I was shocked to find that the Zektor actually DOES WORK as expected.

So again this made me think my Mini ITX had a serial port issue. I grabed a different cross over cable I had and hooked the Mini ITX directly to my laptop and ran HyperTerminal on both machines at 9600 8 none 1. Again I was shocked that the COM1 on my MiniITX actually does work in both RX and TX directions. I was able to send letters from my Mini ITX to the laptop and back the other way.

So then I was thinking well maybe the cable I made was bad. So instead of going directly to the USB to Serial converter with the laptop I connected the Zektor to the cable I made and then to the USB to Serial converter and then to my laptop again EVERYTHING WORKED with my laptop.

So I tried COM2 on my ITX which my 777 works fine on and that did not work with the Zektor either.

Finally I tried to hook the USB Converter up to the ITX as an additional Serial port and it showed up as COM5. I then hook the Zektor up to that port and again it did not work. So no matter if its an onboard port of a serial converter the Zektor does not work with my ITX

So to summarize the connections I tried.

Zektor --> ITX COM1 [Did not work]
Zektor --> ITX COM2 [Did not work but 777 does work]
Zekto -->Serial Converter COM5 [Did not work]

Zektor --> Laptop [WORKS]
ITX COM1 --> Laptop [WORKS]
ITX COM1 --> Custom Cable --> Laptop [WORKS]
Zektor --> Custome Cable --> Laptop [WORKS]

So everything tells me that my cables are good and the Zektor is good and the Mini ITX Serial port is good but for some reason the Zektor and Mini ITX don't like each other.

Anyone ever heard of such a thing?

I'm fresh out of ideas other than running a serial cable to my master server and buying another USB Converter to use with that computer. I use the converter I have for other things so I would need another one.

 

[Brightan]

if you are using the same USB to RS232 converter for both your laptop and your PC and it
only works on your laptop then you have ruled out it being a hardware issue, right? The
next question would be what software are you using to test, the same on both? If you
are using a terminal program, a quick test is to short out pins 2&3 of the D-9 connector
on your RS232 port and anything you type on the terminal will echo back. This will
confirm you are talking to the right port at least. The only other issue I can think of is to
question what kind of handshaking the device is expecting and if the test software
(or terminal program) differs in that regard between the two machines.

 

[Squintz]

That's sort of what I did using the cross over cable. I connected the ITX to the Laptop and was able to send commands using HyperTerm back and forth. The only software I am using to test the Zektor is Hyperterminal at this point. It's the only software that I can get a visual feedback from. If I send it a V and press return on my laptop it gives me back the firmware version of the Zektor but if I do it from the mini ITX I don't get anything back.

I am running Windows Vista on the laptop which required me to download a free version of hyperterm and I am running XP Pro on the Mini-ITX.

Also, since I used the same USB Converter from the laptop on the mini ITX and that also did not work I am thinking that I can rule out hardware and software issues.

One thing that I am thinking is that maybe the Mini ITX or Zektor is not putting out enough voltage on the RS232 port for the other to be able to see it. But then again I did use the USB converter also and th Zektor works on the laptop so that would leave only the Mini ITX to be the problem.

I'm so darn confused about this it's not funny. I'm actually very familiar with how RS232 works and non of this makes logical sense to me.

 

[gatchel]

Even if you use a crossover (null modem cable) from computer to computer you may not have all of the necessary conductors to use the hardware handshake lines. You can communicate using no flow control with just 3 wires (GND, TX to RX and RX to TX). You may need to try a different style crossover cable. Belkin makes a null modem cable with a DB9 and DB25 on both ends and it works well for testing things like this. They can be found at CompUSA or MicroCenter.

Your other option is to use a device like a Lantronix UDS1100 and Comm Port Redirector to map a virtual comm port to an IP address using ethernet communications from the PC to the UDS1100.

A loop back test on the ITX PC would be another place to start as previously said. Use a small flat blade screwdriver, set up HT with the same comm port specs using "No Flow Control". Once open short pins 2 and 3 while typing shen shorted, the characters you are typing will show on the screen. When you remove the screwdriver they will stop. This way you know your port is good. You can also make a loop back plug with a DB9 that can handle hardware FLow control lines and test with this also.

This page has some pinouts to help...

http://www.pccompci.com/rs232-cable-technology.html

 

[Brightan]

ok, so if the hardware is the same and you're using a similar hyperterm
program and looking at the manual there is no hardware handshaking
required... the only other thing I can think of is that the protocol requires
an ascii command followed by a <CR>... Is it possible that the version
of hyperterm on your PC is only sending <LF> and not <CR>? On my
version if you go under File/Properties/Settings/ASCII Setup/ there is
a check box for "Send line ends with line feeds"

 

[gatchel]

It could be. Carriage return and line feeds could be the issue depending on what chcracters the Zektor is looking for. I don't know much about the Zektor. Do they have a tech support line you could call? That may be your best bet.

 

[Squintz]

Thank you all for your help...

I think I figured it out. Not really sure how I stumbled across this stuff but here goes my explaination. As usual the hardware correct and the users are wrong.

The first problem is that the current HDS4.2 driver does not use the same protocol as my current HDS4x2 hardware. I actually suspected that might be the case at first which is why I pulled up hyperterminal to play with the protocol.

The second problem, i'm not so sure it should have been a problem. In my Hyperterminal configuration I had 9600 8, N, 1 and Hardware Flow Control. The Zektor does not like the hardware flow control. I figured this out when I typed a bunch of random keys while looking on my oscilloscope for a signal and when I did not see anything coming from the mini-ITX I plugged the cross over cable back up between the Mini and Laptop and without having to press any keys the hyperterminal screen on my laptop filled up with characters. So this hinted to me that something weird was going on with the control lines.

So in hyperterminal I had to turn flow control to None.

Now I have to rework the PDL driver for the new protocol.