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Com port wiring.

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.
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Comments

  • John GonzalesJohn Gonzales Junior Member Posts: 609
    B_Clements wrote:
    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.

    Good advice. Sounds familiar: another issue here

    --John
  • FrankieFrankie Junior Member Posts: 71
    I had the same problem with a NEC plasma.
  • wcravenelwcravenel Junior Member Posts: 114
    I swear nobody is paying me to say this:

    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
  • alexanboalexanbo Junior Member Posts: 282
    I use CAT 5 to DB9 connectors that let me pin the connection any way I want. They're a lot cheaper then the AMX ones.

    Andre

    wcravenel wrote:
    I swear nobody is paying me to say this:

    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
  • Thomas HayesThomas Hayes Junior Member Posts: 1,164
    I had the same problem earlier this year. Trying to same time using pre-made sub-D 9's. Caused the extron switcher to go into 'automode' and not able to switch. Now were back to the old way, build every cable. I must say that was one thing I did like about the NXI series was the quick-screw type connector. Handy if you mixed Tx, Rx.
  • I had the same problem earlier this year. Trying to same time using pre-made sub-D 9's. Caused the extron switcher to go into 'automode' and not able to switch. Now were back to the old way, build every cable. I must say that was one thing I did like about the NXI series was the quick-screw type connector. Handy if you mixed Tx, Rx.

    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
  • Thomas HayesThomas Hayes Junior Member Posts: 1,164
    Agreed Brian, The re-introduction of the sub-D was IMHO was a step backwards. However I think you hit the nail on the head with respect to costs and residential dealers. Just the time saved to reverse the Tx Rx wires justify any increased cost of using the Phoenix connectors.
  • Agreed Brian, The re-introduction of the sub-D was IMHO was a step backwards. However I think you hit the nail on the head with respect to costs and residential dealers. Just the time saved to reverse the Tx Rx wires justify any increased cost of using the Phoenix connectors.

    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.
  • Spire_JeffSpire_Jeff Formerly Caffeinated Programmer Posts: 1,917
    I don't mind using the RJ45-DB9 adapters. Even if I had pheonix connectors on the processor, I would still need to figure out which wire color goes to which pin. With the adapters, I have documented which wires go where for all of our common devices. I can give configured adapters to our installers and tell them to terminate the CAT5 cables with 568B standard and plug them into the adapters.

    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
  • KennyKenny Junior Member Posts: 209
    AMX STS equal

    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.
  • JohnMichnrJohnMichnr Junior Member Posts: 279
    Ya know - the AMP Crimp on 9 pin stuff is not expensive, and once you get good with the extraction tool it is easy to flip pins 2 & 3. I just make all my cables.

    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.
  • mstcmstc Junior Member Posts: 6
    Break off unused pins on premade cables - when gender permits

    Then you can buy cheap cables (www.addlogix.com).

    I like the cat5 - rj - adapter method. I also have a pin tool for those
  • SpannertechSpannertech Junior Member Posts: 53
    I've been working on a job where the installer, at my suggestion, tried the screw terminal BTX connectors that Kenny mentions. This job has a ton of plasmas. They've been a godsend - fast to terminate, easy to see how they're wired, easy to swap pins. Yes the connectors are expensive but save time.

    OP
  • toddttoddt Junior Member Posts: 28
    I have found this to be a pretty good rule of thumb, and it may not always be correct, but I have found that it work. We all know that you have to connect a female connector to the master, so if it is a female connector that connects to the device, then it will need to be a null modem or pins 2 and 3 flipped on one end. If it is a male cable that connects to the device it is a straight thru connections, pin 2 to 2 and pin 3 to 3. Now this does not solve the installers solder, crimping ect wrong, but if you at least tell them this, it is a good start.
  • Joe HebertJoe Hebert Junior Member Posts: 2,159
    Yes, if every manufacture follows the ?standard? then the connector genders can be used as a good rule of thumb. If one side is male and the other is female then you need a str8 cable. If the connectors are male/male or female/female then you need a crossed cable.

    I?ve also used the tip below that was posted by Leo last year

    http://www.amxforums.com/showthread.php?t=1052
  • Thomas HayesThomas Hayes Junior Member Posts: 1,164
    Joe Hebert wrote:
    Yes, if every manufacture follows the ?standard? then the connector genders can be used as a good rule of thumb. If one side is male and the other is female then you need a str8 cable. If the connectors are male/male or female/female then you need a crossed cable.

    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. ;)
  • annuelloannuello Junior Member Posts: 294
    FWIW, I use premoulded fully wired from the NI-3000s to the projector location, 10-30m long. I then make a crossover cable which is installed at the projector. When I need to do an emergency swap (with a different brand of projector) it too has a crossover cable to suit it's own pinout & genders. The crossovers are not fully wired, just pins 2, 3 & 5. I've had no trouble with interference in the cable forcing the NI-3000 into 485 mode.

    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 MoodyChip Moody Junior Member Posts: 727
    Definately a good rule of thumb - applies about 95% of the time in my experience... Don't try using it on a Polycom VS4000 though.

    - Chip

    toddt wrote:
    I have found this to be a pretty good rule of thumb, and it may not always be correct, but I have found that it work. We all know that you have to connect a female connector to the master, so if it is a female connector that connects to the device, then it will need to be a null modem or pins 2 and 3 flipped on one end. If it is a male cable that connects to the device it is a straight thru connections, pin 2 to 2 and pin 3 to 3. Now this does not solve the installers solder, crimping ect wrong, but if you at least tell them this, it is a good start.
  • MRoedMRoed Junior Member Posts: 9
    Reasonably Priced RS-232 Terminal Adapter

    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
  • VLCNCRZRVLCNCRZR Senior member Posts: 216
    phoenix vs. DB9

    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.
  • Chip MoodyChip Moody Junior Member Posts: 727
    This site might be worth checking out for those following this thread...

    http://www.easyadapters.com/page2.html

    Currently they only have female versions, but claim that male are on their way shortly.

    - Chip
  • ColinColin Junior Member Posts: 51
    232 Heaven

    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.
  • Spire_JeffSpire_Jeff Formerly Caffeinated Programmer Posts: 1,917
    I just use RJ-45 to DB9 adapters. I get them from a local wire distributor. Within the rack, I just use a patch cable. For longer runs, just use a CAT5 cable and terminate like a standard network cable. I have adapters to go to DB9M, DB9F, DB25M,DB25F, and even DB15M and DB15F (not HD). The adapters have 8 wires with pins/recepticles that are color coded and you just insert the wires into the numbered holes. If you find that you need 2 and 3 switched, there is a little insertion/extraction tool that let's you easily do it. Here is a link I just found on google for a company that sells the modules I refer to: http://www.sfcable.com/catalog/wholesalecables/31D1-B1.html .

    I have not had any problems with the adapters and have run lower BAUD rate connections well over 50ft (9600 Baud).

    Jeff
  • glr-ftiglr-fti Junior Member Posts: 286
    I use DB9 to RJ45 adapters as well however this is a very attractive price. I had been getting them from Black Box but they were about $8 a piece!
  • JoeJoe Junior Member Posts: 99
    I agree with Colin. If a projector can dynamically swap the horizontal and vertical sync if the wiring is landed wrong, then it would seem easy to have a Netlinx controller swap the Tx and Rx on the com ports. This could be internally through code, much like setting the baud rate, or have a physical switch on the back of the unit next to each port.
    Either way, this would save a lot of time and frustration onsite.

    Joe
  • DHawthorneDHawthorne Old Timer Posts: 4,584
    Joe wrote:
    I agree with Colin. If a projector can dynamically swap the horizontal and vertical sync if the wiring is landed wrong, then it would seem easy to have a Netlinx controller swap the Tx and Rx on the com ports. This could be internally through code, much like setting the baud rate, or have a physical switch on the back of the unit next to each port.
    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.
  • JoeJoe Junior Member Posts: 99
    DHawthorne wrote:
    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
  • DHawthorneDHawthorne Old Timer Posts: 4,584
    Joe wrote:
    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
    It still comes down to a limitation of the actual chip. I'm sure they just use a generic RS-232 chip and don't want to produce their own for a feature like this. Generic RS-232 chips have been on the market for ages, I somehow don't see any dramatic re-engineering of them happening, especially since it is a dying comm method.
  • Joe HebertJoe Hebert Junior Member Posts: 2,159
    DHawthorne wrote:
    Generic RS-232 chips have been on the market for ages, I somehow don't see any dramatic re-engineering of them happening, especially since it is a dying comm method.
    RS-232 is a dying comm method?? I must have missed that memo.
  • Spire_JeffSpire_Jeff Formerly Caffeinated Programmer Posts: 1,917
    According to the people at pianodisc, the only method for control in the future will be a builtin webserver running most likely a flash site... and that is because MS Media center can work with it really well. (Sorry, couldn't resist a little venting). I think the move to IP communication is very realistic, but serial communication is still more reliable because the IP communication requires a higher technology medium for connections. It's a lot easier to control the communication pathway in a serial connection.

    Jeff
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