The VAMS-0808 matrix switcher and determining its protocol

A significant part of the whole-house audio system is the matrix switch that allows any audio input to be listened to on any audio output. I’ve been looking for a suitable switch for several months now (by suitable I mean cheap enough, but still capable). My requirements are that it has 8 inputs, 4 outputs and RS232 support.

Once again, eBay has proven it’s worth and I’ve found something for a lot cheaper than my previous find. It has 8 inputs, 8 outputs, RS232 support and includes composite video switching too. S-video switching would have been nice, but that feature seems to double the price so I’m happy to go with the compromise of composite video.

Of course there’s always a hitch with these low-cost items made in the far-east, and it’s almost always that the websites are absolutely rubbish – crafted to work only in IE, badly structured, lacking any useful technical information and generally broken. Thankfully, Google has come to the rescue and I’ve managed to find the software that controls the VAMS-0808 (IE is required, and the installer doesn’t even open in Vista – works OK in XP though).

I’ve got a Virtual PC with XP installed, just to connect to work’s VPN which until recently didn’t have a Vista client. One of the handy features in Virtual PC is the ability to map COM ports to physical ports, named pipes or a text file. I set COM2 to redirect to a text file, and voila, I now know how the software talks to the switcher.

Communication protocol for the VAMS-0808 (not tested yet)

This is what I’ve figured out so far:

All commands start with a 0 (zero), and are committed with a Windows new-line (\r\n). Some actions require multiple commands in order, for example channel switching. An output channel selection command must precede an input channel selection command.

  • 0CO1 – 0CO8: Select output channel 1-8
  • 0ALL: Select all output channels
  • 0CI1 – 0CI8: Set input channel 1-8 for currently selected output channel
  • 0OFF: Disconnect currently selected output channel (input channel 0)
  • 0VCS: Subsequent commands switch only video
  • 0ACS: Subsequent commands switch only audio
  • 0AVS: Subsequent commands switch both audio and video
  • 0LOO: Disable hardware lock
  • 0LOI: Enable hardware lock

I have no idea if the switch actually returns any status codes since I haven’t got it yet, but hopefully it’ll be on it’s way to me soon!

Edit: 0OFF actually means disconnect the selected channel, not disconnect all channels. Also: woo! It’s arrived! Very speedy delivery indeed.

Re-running cables


There are two main wiring routes that are part of my ongoing project to wire up our house for A/V and data distribution – one goes from the bottom of my wardrobe directly down to the room below, and the other goes across a short stretch of the landing and down into the pantry.


Until yesterday, the 4 x speaker and 6 x CAT5 cables going to the pantry were laid under the carpet, then pushed down through a hole in a floodboard and the corresponding hole in the pantry ceiling. The reason for this was simply that it was too much work at the time to run the cables properly, i.e. beneath the floorboards. At the time when I was running the cables, we weren’t living in the house so I only had relatively short visits in which to do the work.

I spent most of yesterday improving the situation by pulling up flooadboards, drilling holes in joists and reaching around in the dirt. All but 2 of the cables that were fed under the carpet are now out of sight under the floorboards of the landing. The remaining 2 cables are CAT5 feeds to bedroom 3, which take a slightly different route to the main runs and are already connected at both ends.

Continue reading “Re-running cables”


I felt the urge today, as happens every now and again, to add to my music collection. Up to today my collection has consisted only of CDs, which I’ve ripped to MP3 for playback on my computer and my iPod. While I was looking around for albums to buy, I checked out to see how their prices compare to Amazon for some of the rarer albums.

Most of the albums I were after need to be imported, but earlier this week Play launched their own DRM-free download service. I managed to buy 3 albums by Ugress for £1.95 each! Up till now I’ve avoided download services because for only a few pounds more (or even a few pounds less) I can have a physical CD to serve as a backup and something to look at. The bargain download albums I found were just too good to pass up though, and since they are DRM-free I’m not restricted in any way with how I can play the tracks.

To keep the tracks safe, since there isnt a CD version, I’ve added them to their own folder on my fileserver. This folder will be added to the backup system, so they will be included in the daily tape backups.

Purchasing the albums is no different to the normal process on Play, and I included some CDs with my order that should arrive in a few days (Morcheeba – Dive Deep, Plaid – Spokes, Plaid – Rest Proof Clockwork). After going through the checkout process, the confirmation screen is slightly different and 2 emails are sent – one for the physical goods and one for the downloads. A list of all purchased tracks is available in the ‘My Account’ section of the site, where the tracks can be downloaded individually or in one big zip file including album art.

Downloading of the zip file is streamed, so you don’t get any indication of the size of the file as it is downloading (since the size of the file is not known when the HTTP response headers are sent) but the speed was pretty impressive. I got 1MB/sec+ (not Mbit – I’m on a 20Mbit connection) which would probably have maxed out my connection if I weren’t downloading/uploading other things at the time. As the popularity of this service increases, I suspect that the download rates will drop in a similar way that iTunes-hosted downloads can sometimes slow to a crawl.

One criticism of the ‘download-everything’ zip file is that the tracks are not separated into directories, so I had to manually separate out my 3 albums. This could be for some compatibility reason, or just that the developers didn’t know how to add folders to a zip file. I’ve programmatically created zip files at work using SharpZip, and the process of adding folders is not as straightforward as you might expect.

Overall I think the service is great value for money. It competes well with iTunes, at 9p cheaper per track and with some real bargains for albums if you look around. The Play site could still do with a few extra features to make browsing a little easier, such as deeper categorisation, easy access to albums by artist, the ability to order by price, and the ability to browse categories rather than just getting a summary of what’s popular, new etc.

Work-sponsored toys

I finally got to play with an iPod Touch yesterday, courtesy of a project I’m working on at work. The interface is beautiful and slick, and I was amazed at how thin it is compared to my previous generation iPod Video. Sadly we don’t have wifi at work yet, so I wasn’t able to try out Safari, YouTube or iTunes on the device.

One of my colleagues was considering whether to get a Touch or Classic to replace his early-generation one that had broken, but since he has quite a large collection of music the limited 16GB capacity of the largest Touch was just not enough. Will there be a 32GB version I wonder? If I got one (which I’m very tempted to now!) I could manage with the 16GB version, but I wonder how many people are being put off by the relatively small capacity?

I’m also going to be trying out an Archos (with wifi), a Creative Zen and a Walkman. I doubt any of them will live up to the standard of the iPod. I may report back with some brief reviews.

MacWorld excitement

I’m normally only mildly interested in what comes out of MacWorld, but this time around I’m pretty gripped. I’m now running out of reasons NOT to buy an iPod Touch, thanks to the missing apps from the iPhone now being available through a software update for the iPod Touch. The only reason I have left is that I only bought my first and only iPod about 5 months ago.

The other thing I’m waiting for is an announcement of the release of the SDK for the iPod Touch. This will allow me to develop the iPod Touch remote control as a native application. I’m not sure of the release date of this yet, and I’ve not seen it mentioned in any articles about MacWorld so far. Here’s hoping for it to come soon!

Resurrecting a dead amplifier – the continuation


At the end of last year I tested the prototype of the matrix audio switcher, in the process blowing up part of the amplifier that powers the speakers in the living room. After investigating the damage, I found a great site to buy the replacement parts from. They arrived before Christmas, but I didn’t get around to installing them until recently.


The new transistors are exactly the same as the dead ones, so it was just a matter of unsoldering the old ones and replacing them. The nice chunky pads (compared to all the SMD boards I’m used to handling as computer parts) were lovely to work with, and the work was done in a matter of minutes. Minutes + £6 of parts = one big saving over a new amplifier and a lot of waste electronics. If only all devices were this easy to fault-find and fix.


With a fire extinguisher at the ready and my adrenaline gland just waiting to explode, I switched on the repaired circuit and ….. near silence, just the sound of the fan – it worked! Now that both channels are actually wired to something rather than one of them shorting out, the sound coming out is pretty good. In a few months the whole system should be up and running.

Attempting Crossfire


A couple of months ago I bought Crysis for my PC. My PC has a reasonable spec, with a dual core processor, as much RAM as 32bit Windows can support without crashing and a mid-range graphics card (X1950 Pro). However, Crysis could barely run with this spec even on the lowest settings. Setting up Crossfire should approximately double performance.

When I last upgraded my computer, I spent quite a bit of time researching motherboards, looking for ones with Crossfire support in particular. Crossfire motherboards have 2 of the larger PCI-X slots, though they don’t necessarily both run at x16 speeds. The X1950 Pro card that I already had supports Crossfire mode without having to purchase a special master card – all that is needed are two identical cards.

The card I already owned had just 256MB RAM, but when I purchased it’s companion card there were only 512MB versions available. It was a bit of a gamble, since the configurations weren’t identical, but fortunately Crossfire mode worked beautifully. When in Crossfire mode, the cards appear as one single card to Windows with 256MB RAM, but with a significant performance gain.

I’m not going to bother with taking benchmarks, but I can confirm that Crossfire did help run Crysis on low settings. I think to run it on highest settings I’d probably have to spend quite a chunk of cash, which I can’t really justify at the moment.

This test of Crossfire was only a temporary setup because the new card is really noisy and I had to borrow a more powerful power supply from another computer – Crossfire mode requires a PSU that can supply at least 550W. So until I can afford to buy another power supply, the second card is sitting on the floor underneath my desk.

What’s next?

The Homebrew Challenge gave me a reason to progress my projects, but over Christmas things have slowed down. Winning the competition has given me some money from the sale of my old car, so it seems fitting that the money is put towards finishing the current projects. This is my plan for the projects over the next 2 years.

Purchases Actions
January 2008 Zone 2 amplifier, Zone 4 amplifier Improve rack ventilation
February 2008 Zone 3 amplifier, DVI/USB KVM
March 2008 Matrix switcher
April 2008 4u blanking plate, 1u blanking plate Write control software
May 2008 Write control software
June 2008 Netiom xAP Write control software
July 2008 Write control software
August 2008 Outdoor IP camera
September 2008 X10 modules
October 2008 Outdoor IP camera
November 2008
December 2008
January 2009 Netiom xAP + sensors
February 2009 Netiom xAP + sensors
March 2009 Netiom xAP + sensors
April 2009 Netiom xAP + sensors
May 2009 Netiom xAP + sensors
June 2009 Netiom xAP + sensors
July 2009 Netiom xAP + sensors
August 2009
September 2009
October 2009
November 2009
December 2009

I have purchased the 2 amplifiers for this month from eBay, but haven’t got around to the ventilation improvements as yet.

First prize


A few weeks ago I entered the Homebrew Challenge on The competition was centred around technical projects that people have done in their spare time, so I submitted my projects. The prize was a £20,000 Toyota Prius (a petrol-electric hybrid) courtesy of Intel. This competition was really the spark behind my push to get this blog going with information about my projects and ideas as well as some incentive to progress the current projects, so at the time I thought that even if I didn’t win a lot of good would have come out of it. With the permission of ZDNet the posts on this blog were replicated in the Homebrew Blog. The Homebrew Blog is a new community blog on the ZDNet UK site, which gathers together homebrew-related posts from several blog authors. As far as I’m aware there aren’t any other similar collaborative blogs out there for this subject matter. If you know of any though, please let me know.

After a couple of weeks of DIY and blogging I received a call from the community manager at ZDNet, Karen Friar. A few seconds later I stood on the 1st floor landing of our building in amazement at the news that I had won the competition. I had won a £20,000 car! Naturally my parents were the first to know, alongside my friend Matt who was within earshot of the conversation. Needless to say most people couldn’t believe what I was saying – nor could I. I had told a few people at work that I was entering the competition, mostly so that I could finally explain the purpose of all my wierd deliveries, but normally such an act combined with getting-my-hopes up would just result in disappointment – but not this time!

The following Tuesday I had the day off work to demonstrate my project to the editor of and have it recorded on video. It was nerve-wracking to say the least, but Matt and Ashley were really down-to-earth and nice guys which put me at ease a little. They were also quite knowledgeable about technology, but in hindsight that shouldn’t have been such a surprise with them being from behind a well-known technical site.

The video has been edited together, and is available on the ZDNet UK site (on the homepage as I write this). I’m not photogenic at all, so multiply that problem by about 25 times per second and it results in me not being very videogenic either. Fascinating to hear that my voice is lower than I thought though! Do I really sound like that? I’m going to stick to working behind the camera rather than appearing in front of it.

Originally the car was supposed to be delivered while the video was being shot, but it had to be delayed. The car arrived on the Thursday from Croydon. Another pleasant gentleman drove it to my house and explained pretty much everything about the car – though it still hadn’t sunk in at that point that the car was mine. I had to get straight off to work though, so I didn’t get chance to drive the technology-packed £15-a-year-tax 65-mpg-combined blue car until the weekend.


This is my first automatic car, so my first experience at driving it was a little jerkey. I’m glad I didn’t leave the driveway that time, though I almost went through the hedge. The brake is extremely sensitive, especially at low speeds. For the record my previous car was a 4-year-old 1 litre Corsa (a nice little car) and before that an 11-year-old 1.4 litre Astra (a battered, manual-everything car that’s been through almost the entire of my mum’s side of the family). The first upgrade was a major step, and this one is a fantastic leap!

I have now driven the car on 3 trips, ferrying the family about. It’s a real pleasure to drive. No more aching foot from controlling the clutch in queues! I’m still getting used to it, so I can’t even use the steering-wheel mounted AC/audio/navigation/phone controls at the moment. The sat nav has had one chance so far, and it was OK that time. I’ve programmed it to get me to my next destination on new year’s eve in the middle of Birmingham. That should be the real test for it. I wouldn’t dare venture into Birmingham without satnav.

I’ve already thanked them many times, but thankyou again to ZDNet UK and Intel for such a great competition and a fantastic prize. It has really made my Christmas.