On Tue, Dec 9, 2008 at 4:00 PM, Ross Tucker <rjtucke(a)gmail.com> wrote: Well, you could look at "Votrax" on Wikipedia. Allegedly, the first words spoken by a Unix system at Bell Labs, using its Votrax synthesizer, were "file not found". Things that are now known as "sound cards" were called A:D and D:A converters back in those days. And there were a fair variety of them available for both Unibus and Qbus systems. The vacuum-tube circuits may be running from 350 VDC but somewhere there are low-level inputs from which everything is amplified. Think microphone. carl -- carl lowenstein marine physical lab u.c. san diego clowenstein(a)ucsd.edu

In addition to the DECtalk standalone device, there was a Qbus module called DECVoice (DTC04) that was intended for telephone systems (voice response systems). I have the module in my personal collection; unfortunately, what I've been told is that there's a lot of others' intellectual property in the software (it's a microcoded device) so it would be a serious challenge to get the code to run it - too bad. -- Ian ________________________________________ From: pups-bounces(a)minnie.tuhs.org [pups-bounces(a)minnie.tuhs.org] On Behalf Of Ross Tucker [rjtucke(a)gmail.com] Sent: Tuesday, December 09, 2008 6:49 PM To: pups(a)minnie.tuhs.org Subject: [pups] PDP-11 / vacuum tube interface Dear all, (This has got to be the strangest cross-post I've ever done.) I have just taken a bet from a friend to challenge my geekiness. I was telling him about my love of Vintage Technology and he proposed that I combine two hitherto separate hobbies and see what happens. The topics: the DEC PDP-11 minicomputer (vintage: 1970s) and vacuum-tube ham radios (vintage: 1960s). I do sincerely apologize for cross-posting, but I am rather younger than either of these technologies (vintage: 1984) and this seems like a monumental challenge. My question for y'all: how could I possibly design+build a project that uses both of these technologies? My thought is to port some radio receiver Digital Signal Processing (DSP) application into PDP-11 assembler, compile and run it via emulator on my PC, then use it with the vacuum-tube regenerative receiver that I built a few years ago... Does anybody know if PDP-11 UNIXes even had the capability for a "sound card"? Or, to get ambitious, I would LOVE to design some interface circuitry between PDP-11 digital circuitry and vacuum-tube electronics... The challenges are legion: the tube side of the circuit operates around 350V DC levels with radio-frequency (RF) signals at 7 MHz (almost the clock rate of some PDP-11s!) and I don't have the DEC Handbooks, but I'm pretty sure that even those ancient pre-TTL circuits operate below 350V! So... any, er, "ideas"? Best regards, Ross Tucker CCed to: 'glowbugs' list at <glowbugs(a)piobaire.mines.uidaho.edu> _______________________________________________ PUPS mailing list PUPS(a)minnie.tuhs.org https://minnie.tuhs.org/mailman/listinfo/pups

That's a wonderful idea. As has been pointed out there are a number of A2D and D2A boards available for the PDP11. However it would be fun to do it yourself and design one from scratch although getting hold of prototyping boards for unibus or Q bus could be a bit difficult these days. You would probably have to down convert your RF to audio to keep everything in the realm of what the PDP could handle though something like PSK should be able to be resolved, morse should be a doddle. Have a go, this is seriously pointless geeky stuff and as a result huge fun. Robin rjtucke(a)gmail.com wrote:

If the intent was to be the first one to wed computers and vacuum tubes, you have missed the boat by several decades. I, and I am sure many others did it long ago. I ran HF AX.25 Packet Radio on my Heathkit HW-101. Of course, if the desire is to wed the PDP-11 and vacuum tubes, if it hasn't been done already the same could be done. I would bet I could put an old version of the KA9Q software on a PDP-11 running BSD or even Ultrix-11. And then, fire up my HW-101 (yes, I still have it) and the deed is done. Of course, I could also use my HF rig which is also of the vacuum tube genre. Drake Twins. :-) bill -- Bill Gunshannon | de-moc-ra-cy (di mok' ra see) n. Three wolves bill(a)cs.scranton.edu | and a sheep voting on what's for dinner. University of Scranton | Scranton, Pennsylvania | #include <std.disclaimer.h>

But only if you have Joan Collins to inspire you.

Hello! (Resend because a member missed it.) The term is Trekker, Kevin. And it takes place during the second act of a very important episode. But I freely admit that I am interested in this decidedly strange mix of technology. -- Gregg C Levine hansolofalcon(a)worldnet.att.net "The Force will be with you always." Obi-Wan Kenobi   On Behalf