Com port wiring.
[Deleted User]
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I recently took a support call concerning the inability to receive data on an NI-3000 com port. After some basic troubleshooting eliminating a defective controlled device it was determined that the integrator was using a pre-made DB9 cable that used all 9 conductors. The device worked fine with Hyperterminal and this cable. Had to be a bad NI-3000, right?
It turns out that the controlled device only needed Tx, Rx and Gnd to function properly, but an unintentional handshaking connection from the NI-3000 was preventing data from being sent from the device.
Moral of the story, don't use pre-made cables. Only connect the wire conductors that are specified by the device manufacturer. The reason is that the typical AMX com port is a non-standard dual purpose connection supporting both RS232 and RS422 wiring.
It turns out that the controlled device only needed Tx, Rx and Gnd to function properly, but an unintentional handshaking connection from the NI-3000 was preventing data from being sent from the device.
Moral of the story, don't use pre-made cables. Only connect the wire conductors that are specified by the device manufacturer. The reason is that the typical AMX com port is a non-standard dual purpose connection supporting both RS232 and RS422 wiring.
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Comments
Good advice. Sounds familiar: another issue here
--John
The AMX part STS is a pricey little DB-9 with a nice shell around an incredibly convenient screw terminal connector. I figure the price is less than my time to mess around with soldering or sticking pins into a make your own connector.
Bill
Andre
Hi Tom,
I agree the Phoenix connector is more flexible. I believe extra cost and residential dealer preference played big in the decision to use DB9 connectors in the first place. But, what is the point if you can't use premade cables.
This design has always been one of my pet peeves with the Axcent 3 and the NI-xxxx series.
Brian
I wonder if a dealer would be willing to pay more for a version with Pheonix connectors instead of the DB9? I suspect it would add at least $100.00 to the cost. But, installation timed saved could easily make up the difference.
The only place that I prefer pheonix connectors are when I need to short the handshake pins on a device, but so far I only have that problem on Fujitsu Plasmas
Now, if the devices we connected to had pheonix connectors, I would be all over pheonix connectors on the processor.
Jeff
BTX makes a similiar db9 to screw terminal. This is very useful when trying to figure out if 2 goes to 3 or 3 to 2 or 3 to 3.
The part number is CD-DB9FST. I think the cost was $11 and $23 for the Male version.
Not sure why one is more than the other.
I too just ran into a situation last week where the dealer was using all premade 9 pins and the product (infocus projector) would not run.
Then you can buy cheap cables (www.addlogix.com).
I like the cat5 - rj - adapter method. I also have a pin tool for those
OP
I?ve also used the tip below that was posted by Leo last year
http://www.amxforums.com/showthread.php?t=1052
That would be so nice but the only standard I have seen in this field for almost 20 yrs is the 'only standard is no standard'. Just depends what side of bed the engineer got out of bed.
I also carry with me a D9 male to female "adaptor" with a DPDT switch on lines 2 & 3. With a few gender changers I can connect any gender to any other gender, and make it crossover or straight though. It makes the "plug & play" approach soooo much quicker.
Now I just have to figure out how to have several projector modules running and have them dynamically attach/release the physical port, to save me recompiling when doing such a swap... That would be quite neat!
Roger McLean
- Chip
We have had similar experiences with using premade cables. For a long time we have soldered on DB-9 connectors. More times than I would like to admit we have had to reverse pins 2 and 3 afterward.
The cost of the DB-9 to terminal block adapters have always prohibited us from going that route. So, we developed our own adapters. They are available for a much more reasonable price (between $3.75 and $5.00). Currently, we have two female versions available on our website. We will be adding a male version in the next couple of weeks. Check our website out at (www.easyadapters.com). We have some helpful information on terminating control cables as well.
Thanks,
Mark
Anyday of the week, I would rather have mini-phoenix connections
to work with for a few reasons:
1) The ease of cable prep and termination (strip-tin-tighten).
2) No soldering necessary for "less-than-proficient" field techs.
Typically, I provide pinouts to installers to run and terminate
the control wiring, but quite often have to make many corrections
once I go onsite to load and test the programming. It would take
me an hour to describe the kinds of things that I have found.
3) Ease of modification if necessary.
4) Ease of connector seating (I always hate trying
to find the tweeker slot on a DB9 in a dark rack, and God forbid that you
drop one of those small screws).
There is only 1 reason that I like DB connectors, and that is the
ability to easily extend or connect another cable for testing purposes.
http://www.easyadapters.com/page2.html
Currently they only have female versions, but claim that male are on their way shortly.
- Chip
Now what would be really really good is if you could determine the crossover in the code at Data_Event stage - theoretically possible but would then fall out of standards as far as DTE / DCE. Would probably lift the cost of the controllers but the time spent in resoldering the pins after taking off and putting back on the backshells would pay for itself and therefore on-site installers can have the standard wire pin for pin and we'll take care of the rest! My opinion is that if the guys are bad at soldering then I'd be shy of letting them at the clients expensive equipment.
I have not had any problems with the adapters and have run lower BAUD rate connections well over 50ft (9600 Baud).
Jeff
Either way, this would save a lot of time and frustration onsite.
Joe
It's not quite the same ... the TX and RX lines on a serial port just go high and low with the data flow. The port itself can't detect which end the signal is coming from, serial hardware was never made for it. It literally can't tell that the pulses on it's TX lines are being generated internally or if they are from a mis-wired outside source. Detecting sync, on the other hand, is fairly obvious - it's there or it's not. Now, a switch swapping them out would be handy though. I like the way NXI's are setup with a mini-phoenix, just for that reason; it's easy to swap them. But AMX decided to go back to 9-pins with the NI.
I wasn't assuming that the box could make the determination of where the signals were originating from, it was more of the 'internally swap them if I tell you to' thing.
Thanks for the feedback!
Joe
Jeff