a7a0fcc4   
   From: joe@user.com   
      
   "Kelly Leavitt"  wrote in message   
   news:8475bf9e-abb7-4156-8f7f-1dc01f9cc16f@q25g2000vbx.googlegroups.com...   
   > In July of 1983 Tandy announced the "Tandy Videotex and Office   
   > Information System" that ran under Xenix. It was an early attempt at   
   > a   
   > hypertext system. It used dialup lines and was hosted on Tandy Model   
   > 16b   
   > (and later 6000) computers.   
   >   
   > An 8 port and 16 port multiplexor (that's how they spelled it) were   
   > announced. I don't know if either ever shipped.   
   >   
   > There is some information available in the July 25, 1983 issue of   
   > InfoWorld. There is also an article in "TRS-80 Microcomputer News"   
   > V5,I   
   > 11 (#54 ).   
   >   
   > I used to run one of these for a local company (that I still work   
   > for).   
   > Does anyone have the manuals or software from one of these systems? I   
   > still have the hardware (not the mux, just the 16b and hard drive).   
   >   
   > Kelly   
      
   I didn't know that they ever came with a 16 style machine.   
      
   If I remember this right...   
      
   The original system came with a Model II.  The MUX was a 16 slot Model II   
   motherboard inside a custom rackmount size case.  It had a CPU card and a   
   memory card.  Then there were 4 clusters of 3 boards that were a dual-modem,   
   a 4-channel com board, and another dual-modem.  The 4 channel com board was   
   based on WD8250 chips, similar to the IBM PC, with a single Z80-CTC used as   
   a BRG.  Each modem board would short the IEIN and IEOUT lines on the buss so   
   that the interrupt enable would make it down the bus to the last com card.   
   Since the bus was so long, there wasn't the normal Z80 interrupt enable   
   lookahead circuit on the CPU, instead there was just a long delay.  The   
   memory card was generic Model II.  The CPU was different due to the IE   
   circut, and also had a different ROM that booted from the serial port.  The   
   com boards were custom to the MUX, but could be used in a Model 16 (actually   
   with xenix, the 16 vs 2 didn't matter), but NOT a Model II, due to the fact   
   that they used memory mapping for all the ports they had to support, and   
   TRSDOS wouldn't handle the conflict well.  Xenix had no trouble with it, and   
   in fact there were drivers for the cards on one of the tar disks.   
   Unofficially, of course.  Just like there were drivers for the Model 2000   
   keyboard, and for a small adapter that allowed either Model 1000 or Model   
   2000 Mice/Clock boards to be used on the 5-1/4" hard disk cable...  And the   
   Model II graphics card.  Like I said, all unofficial.  Well, mostly.   
      
   The Model II used for the MUX was generic Model II, and when it booted it   
   just became the 'boot device' for the MUX over the serial port.   
      
   There was a 'service rom' for the MUX that allowed for easy setup of the   
   modems.  (They were 300 baud, answer only.)  On interest...  The service rom   
   had one step that said Wrong Key Bozo, try again if you hit the command   
   sequence in the wrong order...  (There's an interesting story behind that!   
   Not as good as the Rummy Buzzard, but still good)   
      
   The reason I say the MUX setup never came with the 16 type machines is that   
   I don't recall it ever being released on an OS that supported motor startup   
   on the 16.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)