YouTube videos of vintage PDP-11/40, ASR-33, VT05, etc
wacarder at earthlink.net
Mon Jan 21 08:41:28 CST 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'.
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,
Note on my videos that the VT05 (DEC's early video terminal) also
buzzes at the end of the line on long lines.
More information about the cctech