COM-USB alternative – DIY and cheap!

One of the things which really attracted me to the Texecom panels was the ability to interface them directly with the computer – and other things (to be described in a future post). However, in order to do this you need to buy a fairly expensive cable from Texecom – the COM-USB:

Texecom COM-USB

These seem to retail for about £40, although there are some cheaper 3rd party versions on ebay for rather less, which seem to do exactly the same job:


However even this seems a bit steep for what looks a fairly simply USB cable, and the pins on the Premier Elite main board also appear fairly standard.

I then came across this extremely helpful post:

In which the author has discovered that the connector on the board is no more than a straightforward serial connection, with three pins – TXD, RXD and GND – connected. Using a USB-serial converter he was able to get everything working with the official ‘Wintex’ software which is a free download from Texecom.

I took a slightly different approach and bought from ebay a very small board which converts a mini-USB plug into serial with pins and solder points as outputs. It was about £4 delivered.

I bought one of these

I then used an old motherboard header cable directly soldered to the TXD, RXD and GND points on the board above, and connected the other end to pins 3 (GND), 4 (TXD) and 5 (RXD) at the Texecom end. So in other words the data is received by the Texecom on pin 4, and transmitted from pin 5. Once this was all wired up I secured the board inside the casing with a cable tie and ran a USB lead outside the box.

The end result looks like this:

So a very cheap solution which is just as good as the £40 official alternative.

20 thoughts on “COM-USB alternative – DIY and cheap!”

  1. Hello,
    Thank you very much for this information I just found your post and I wish to do the same thing.
    But just a question you used the adapter in 3.3v or 5 v.
    Thank you for your reply
    Best regards

  2. Hi, off topic however I couldn’t contact you directly. For a cheaper alternative to the official Texecom key fobs, then these work perfectly (tried and tested by me). The key is the proximity tags need to be writable ones, rather than the typical pre-programmed ones with a read only ID. Presumably any based on EM4305 will work fine. Five of these cost me £2.19 postage paid.

  3. Thanks for the tip on the key fobs – I’d previously bought some that didn’t work (they must have been read-only). This will save me a bunch!

  4. Yes this should be fine, although you will need to check the pin connections at the other end.

    However a word of warning, I bought three cables very like this a couple of years ago. They worked fine at first but have now all either broken completely or become very unreliable.

    If you only want to use it occasionally then it will probably be fine, but if you want to use regularly or for mission critical things it’s probably worth spending va bit extra.

    Please let me know what you find!

  5. I wouldn’t recommend that cable now after the experience I had flashing the alarm using a similar product. I purchased the cable on eBay and it was advertised similar to the one your are looking at…[i]FTDI FT232RL USB to 6Pin TTL RS232 Serial Adapter Module Cable for Arduino[/i]
    I’ve now purchased a TTL board similar to the one in previous posts and I was able to flash the panel with no issues.

  6. Thanks, I’ll take a look at one of those instead.

    Just out of interest, do you need to disconnect the power and battery before connecting to the COM ports?

  7. Yes, I think these would be fine. I have some quite like these and they are very convenient although I had some reliability problems. These do look different though and they aren’t expensive so I’d say to get them in and see how you get on. I might get some myself!

  8. Hi lads, I have fdti board and I’m try to connect with UDL software . I connect board with Veritas excel ( GND-GND, TX-RX , Rx-TX) but still not working . What I’m doing wrong ? Maybe I need turn on some option in Veritas ? Thanks for help and have nice day Tomas

  9. I’m not sure about the Veritas panels and whether they support this. It sounds like you have done everything right, only possible is that sometimes modules label TX and RX the wrong way round. I’d try connecting TX-TX before giving up!

  10. For those that are connecting to an exciting board, you will need the engineer’s password – obtained from whoever installed the board. If that is not available, there is a small reset button the board. This gives the impression that it resets to factory defaults but it actually just rests the engineer’s password to ‘1234’. You will need to set up a premises account in the software using the default password. It is possible that the password locked by the installer and there is then no way in unless you can contact the installer, or trying random four-digit numbers. I think – but am not certain – that you need to power down the system (including disconnecting the battery) to then power up before resetting.

  11. Thanks Alan. Do you mean the ‘load defaults’ button? I must say I thought that this did reset the whole panel including programming data but it may be different on different boards. It is worth checking the manual for your specific board before doing anything. I had an old ADT panel and for that one you had to hold down some keys when powering up the panel to reset the code, which was quite a job given the long distance between the panel and and the controller!

  12. I’m a texecom installer and happy to help. The UDL passcode is different to the Engineer or Master Code (should be set independant). I don’t think the UDL code is defaulted when you use the Load Defaults button. NOTE: be careful with the Load Defaults button as another usage of it is to completely factory default the panel.

  13. Extraction from the Texecom Premier Elite Installation Manual:
    21: Load Defaults Button
    Press and hold this button whilst applying power to the control panel to load the factory default settings.
    Press and hold this button for 7 seconds with power already on the panel to restore just the Engineer code to the factory setting of 1234. See page 53 for full details.

     Loading the factory defaults can take up to 30 seconds to complete.
    Loading defaults will only be possible if the NVM has not been locked (see page 71 for details).

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