Chris Prosser’s Blog

I like building things. I’ve built several computers before, some silent, so I wanted to scavenge some parts and build up a good system for my livingroom.

In a nutshell, the system is:

• AMD 65W 4400+ CPU (dual 2.3GHz cores )
• ASUS M2NPV-VM Motherboard with integrated Graphics
• 320GB Western Digital Drive
• 2GB RAM
• Vista Home Premium
• IR Keyboard

This should be more than enough power to do 1080p (though I may need to get an aftermarket card, testing will show).

Some additional componentry:

• silent power supply
• Antec NSK-2480 case
• Foam Dampening Kit

My home network setup is pretty straghtforward. I have Comcast Cable internet running into a Linksys WRT54G router. Plugged into the router is a Vonage VOIP adapter. I’ve setup the WRT54G to have QOS and will limit the upstream and downstream bandwidth pretty significantly if someone is on the phone. This was needed to avoid quality degradation and dropped calls.It looks like comcast has stepped things up a little in my neighborhood. I’m getting about 6000kbps down and 200kbps up (I have a limit on that). Not too shabby.

HTPC

My partner and I decided to cancel Comcast cable here in Seattle last weekend. Not only do I not like their politics, but I recently got an HDTV. Seattle Comcast doesn’t really have many HD channels, and watching upscaled letterboxed MPEG-2 content sucks. We investigated DirectTV, but I don’t have line of sight due to a large tree in my backyard.I’ve decided to try and embrace what it looks like to get content via DVD, HD-DVD, and off the interweb. I’m building up an Home Theater PC running Vista Home Premium. These days with NBC Direct, Amazon Unbox, and who knows what else, I didn’t want to limit myself to Apple. Of course I can still run iTunes (just without FrontRow) so it’s not a very limiting choice.Since my job is managing After Effects Engineering, I’m viewing this as partially an incubator to stay on top of where the various players are trying to go with non-broadcast forms of delivery and what, if any, impact that has on my team. I’m expecting this to be an ongoing experience.

The phone system is remarkable in its’ longevity. It was designed and built back before houses had electricity, running water, and vacuum tubes (at least the kind you could use for signal amplification in a cost effective manner).

Early switching offices had very few lights, technicians had to work with a flashlight to repair the electro-mechanical machinery that made the phone system go. The had their own power infrastructure so they could survive indefinitely if grid power went down. They had mercury vacuum tubes that you had to manually rock to get started operating as rectifiers. Voltage regulation (as the phone system wanted around 48 volts DC, though was designed to operate with almost no dependence on actual voltage to account to voltage drop on long subscriber line runs).

My friend Stephanie and I took a tour of the Museum of Communications here in Seattle. It’s located in the top two floors of a running Central Office and is packed from floor to ceiling with old phone equipment (and some radio and teletypes too). Not only that, but a bunch of people who used to work with the phone company volunteer there and keep the equipment operational! Things like the only operational Panel Switch in the world (from the 20’s).  At one point the docent went to demonstrate a Step by Step Switch and the call wouldn’t go through. We rounded the corner and a couple of guys had a panel open and we doing something to it.

How does this tie into my project? The Automatic Electric Type 40 phone (Picture to come later) was built in an era when they had to call it a Monophone. It was unique in that it contained all circuitry to interface with the phone system within the phone itself. Prior to to the introduction of the monophones like the Type 40 and the Western Electric 302, most phones had the ringer and network interface circuitry mounted on the wall independent of the phone. The phone was designed to be used on both dial (tone) networks where you actually got to dial, and no-dial networks where you asked the operator to connect you Sunset-0585, which in another day and age would have connected to my phone.Back in the day when the Type 40 was built, your dialing sequence would look like:

1. Phone on hook. 48VDC (approx) would be present on the line.
2. take phone off hook, line voltage would drop to about 5VDC.
3. Central Office Magic (how physical copper wires are connected between you and recipient)
4. At this point your phone and the recipients phone would be connected by actual copper, headset to headset. The phone company would provide a bias voltage on the phone line. Your carbon button based microphone would change resistance as you spoke, causing a  variable current on the line, and therefore causing the earpiece on the far end to move and them hear your voice.

I’m restoring my Type 40 to work on my Linksys based Vonage/VOIP home phone. Needless to say I have no idea how the VOIP device does all its’ magic. But I do know that the Linksys device supports the analog phone standard used back in the 20’s and can support up to 5 REN for ringing.  Damn cool. Plus that ring is super authentic.

I’ve been pondering the stability of standards and how older analog standards have impressive longevity as compared to some of the endless standards that are thrown at us in today’s digital world.In my professional work I’m continously confronted by the legacy of NTSC and how even with the DTV broadcasting coming up in the USA the 29.97 frame rate created back in the 50’s is still with us. In a further exploration of this space I’ve been working on a number of projects that use legacy analog standards to connect pieces of technology from wildly different era’s, with entirely different goals.As I finish each project I’ll be creating a longer post about it. The projects I have so far are:

1. Tube Amplifer with portable MP3 sound source, using 1V peak to peak analog as the interconnect.
2. 1946 Automatic Electic Type 40 phone connected to Linksys VOIP adapter using Vonage as the service provider. Yep, the analog phone standard from the 20’s is still valid today. Talk about longevity.
3. Theramin->Midi (using 5V control voltage). Long since disassembled.

–chris