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.


An early opportunity to relearn the important principle of reading the manual.

I had installed one of the zones using a smoke detector, again a straight replacement for the old one. The manual said that it used a ‘normally closed’ relay which opened in an alarm or fault condition. So I wired it up (like the other sensors) to the alarm terminals.

For each zone there are two pairs of terminals – two marked ‘A’ for alarm sensing, and two marked ‘T’ for tamper returns. I had wired the detector up to the ‘A’ terminals, thinking ‘it’s a smoke alarm… why would it need a tamper circuit’. Also of course there are no tamper detectors in the smoke alarm anyway.

Cue a load of headscratching, as however I configured the detector in the software it always returned an alarm condition (it comes up as ‘active’). This is an issue because it stops the alarm setting and all I could do to start with was exclude it completely.

Eventually after a lot of searching I found a reference somewhere to using the ‘T’ terminal and this prompted me, finally, to read the manual. I found this:



One change of terminal later, and now everything works fine.

Life’s lessons learned once again

Texecom alarm system – first steps and installation

I’ve just upgraded the alarm system in my house. When we moved in several years ago there was an ancient ADT installed alarm system. This had been monitored by phone, but when we came we pulled out a lot of the wiring and more to the point didn’t want to pay any monitoring charges.

The system has been rather temperamental since then, and I’ve been keen to change it ever since. The reason for doing so is that I’ve wanted something more reliable and higher tech… and also I’m intrigued by the possibilties for tinkering that this offers.

I did quite a lot of research, and I ended up choosing a Texecom system. This seems to be a cut above the normal domestic brands and are clearly used in a lot of professional settings. I wanted to reuse as much of the existing wired infrastructure as possible, and so I needed at least 6 wired zones. I also wanted to option of using a wireless expansion for extra zones, plus as much options for connectivity as possible. I decided to replace all the sensors as well with modern equivalents.

I bought the following:

Texecom Premier Elite 48

Texecom Premier Elite LCDLP keypad

I was surprised how cheap they were – about £90 each. The keypad has a big display, and support proximity tags as well as some zone expansion. The keypads come in all shapes and sizes – you can get brass, metal, chrome and plastic versions, include a range which can be sunk into the wall. I ended up picking the plastic one because it was cheaper and I’m not quite ready to bash big holes in the wall.

Installation was pretty easy – just a question of stripping the old box out and rewiring the old zones to the new ones. Then the fun begins…

Starting again

I’m keeping this new blog to make a note of various interesting things I come across. I am a complete amateur when it comes to computers, electronics or other technology but I am interested in it. I’m always on the lookout for interesting things to do and I hope some of the things I find out as I go along are of interest.

I have learned lots of things over the years and I want to be able to make a note of them, and hopefully help others in a similar situation.

As I write this there are a few projects on the go – I’m working on an improved control system for my domestic heating, and I’ve just installed a new Texecom alarm system. Both of these are stimulating projects and I will try to document some of what I’ve done.

I’d love to hear from anyone else with similar interests