Documentation for the AT&T Sceptre Videotex terminal

woodelf bfranchuk at
Tue Nov 20 14:20:03 CST 2007

Mark Meiss wrote:
> I've just gotten my hands on a working AT&T Sceptre system, which is a
> 1983 Videotex terminal that implements the NAPLPS standard for vector
> graphics transmission (the same sort of graphics that was used by the
> Prodigy online service, if you remember that).  It powers up fine and
> generates the welcome screen, which includes a "Press [Data] to login"
> message.  Once you press [Data], the screen blanks, and I presume that
> it's trying to establish some sort of connection over the RS-232 port.
> I've just started poking at the thing and haven't gotten far, as I
> need to grab a null modem from elsewhere, but I thought there might be
> a chance that somebody out there has the documentation for one of
> these things.  Through searching about, I'm fairly certain that it's
> hardwired to speak 1200/7E1 on the serial port, but what it's
> expecting to hear is the question.  Just a stream of NAPLPS-encoded
> data?  Or is there more negotiation to be done?

I am guessing it hardwrired for 1200/7E1 download and 300/7E1 uploading.
Here in Canada you had more NAPLPS stuff, but NAPLPS terminals where
allways a rare item to be found.

> I have at least found an online source for the NAPLPS encoding itself:

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