YouTube videos of vintage PDP-11/40, ASR-33, VT05, etc - test-drb@ccmp.vtda.org

21 Jan 2008

...
   I never knew
that an ASR-33 had a bell like an old typewriter to 
 indicate that your near the end of the line. Funny! The computers 
 probably had a special microphone to hear it when printing a directory 
 listing :-) 
I though the 'end of line' trigger for the bell was actually an option, 
but that all Model 33s (RO, KSR, ASR) had the bell which was mechanically 
triggered by a ^G character. 
...
 Oh yes, the VT50 series of DEC terminals have a little
relay on the logic 
board. It'spulsed to geenrate the keyclick and sent a square wave signal 
to generate the 'bell' which sounds rather like a 'raspberry'.
-tony 
Maybe I need to make a video of the VT52 with the ^G bell sound.  It
is a strange sound.  We used to write programs on the PDP-11 back in 
the 70s to "ring the bell" under certain conditions (winning a game,
etc.).

Note on my videos that the VT05 (DEC's early video terminal) also
buzzes at the end of the line on long lines.

Ashley