Various fine instruments of the past

Teletype Model 28 Teletypewriter. A mainstay of communications for a generation (the one before mine; I grew up on the '33), the model 28 is a genuine Brick Shithouse. They cannot be killed; you can still buy expendables from Western Numerical Control. Built into a hefty grey-wrinkle cabinet that sits on the floor, the fantastically complex, utterly reliable purely mechanical device spews out upper-case only characters (contained in two 32-character pages) at a breathtaking 60 words per minute; 5 characters per second. You may laugh, but if kept oiled a Model 28 will do this continuously for decades, I am not exaggerating. It makes a lovely sound; I've augmented mine with a bidirectional ASCII(RS-232) to Baudot(60mA current loop) PIC-based converter that also manages the motor, turning it off when done.

It is not exactly portable; I may add casters to mine (really). Here's an overall view, a close-up of the keyboard, how the operator sees the printing; two internal views here and here.

Dynamotors were once a part of mobile-radio reality. Small receivers might use vibrators; but transmitters always had dynamotors. Who even remembers them anymore! A dynamotor is a motor, and a dynamo ("generator" for anyone younger than 90) wound upon the same armature. Hence the clever name. They generate high DC voltages for electron tube plate circuits. It has commutators and brushes at each end, to need servicing and with which to generate copious radio hash (that's RFI if you're under 45) (EMI to anyone younger than 30). Marconi could have used this particular model for his trans-Atlantic test. Some of these were LARGE, hundreds of pounds and thousands of watts. You can hear this very compact model, only 10 lbs. and 70 watts, made by Zenith for Army Signal Corps around mid-war (WWII for you ungrateful, forgetful little hippy bastards), running alas without load, generating 520V into the air. They make a much better sound under load. Yes, you can run them backwards, putting in high voltage and taking out low voltage; but why?

Paper-tape punches were once part of computing, part of me misses the physicality of the medium. I wish I had a Teletype Corp. BRPE ("burpee") high-speed punch, they make a great racket, but only for the sound; they are a major pain, about 16" of rack height and a special parallel interface. However, I have this incredibly modern (mid-1980's!) 8085-controlled punch and reader from GN Telematic, than makes a nice small elegant sound. It's one of my favorite peripherals. Originally set up as 5-level for TWX/Telex service, I tracked down a dealer and got an EPROM to support 8-level ASCII! Worthless! (Actually, I'm currently obsessed with ASCII and it's utopic assumptions; you can see the alleged results) I also have a big, nasty heavy-duty punch I use for punching mylar tape (oiled paper was more common; mylar was reserved for heavy-duty use, such as exercise or boot tapes). It make a LOUD MOTOR NOISE, it is not broken or worn. Listen to my DCI punch here. (PS: I am always looking for more Mylar tape, 1" wide.)

That's all for now. Apologies for the poor sound quality.


WPS HOME