Ann Arbor Terminals was an American manufacturer of computer video terminals during the 1970s and 80s. The Ambassador model was introduced in the early 1980s, standing out in the large computer video-terminal market for providing a display of up to 60 lines on-screen. This contrasts with the 24 lines of nearly all other terminals of the period. The number of lines was selectable in real time from a number of steps in a range from 18 thru 60.

The Ambassador was optionally available with the CRT in portrait/page orientation - the unit presented here being an example - in addition to standard landscape orientation. The 60-line mode was perhaps more intended for the page-oriented version, but was none-the-less readily accessible in the landscape version, though a little tough on the eyes in landscape.

With double-or-more on-screen lines compared to other terminals, the Ambassador was a great programmer's terminal when used with a windowing editor such as Emacs.

The unit presented here is a slightly later model from 1984. The case is scribed with "CSC 284", a sticker on the side announces "Purchased with the assistance of NSERC" (Natural Sciences and Engineering Research Council of Canada), and a further sticker indicates the unit was supplied by TRACAN Electronics of North Vancouver, B.C.

Contents (this page): Photos

Sub-pages: Unit Log Analog Board (Later Version) Schematic (pdf)

References / External Links: Ambassador material at bitsavers. Ambassador at Terminals Wiki.

Photos

Front-on view, 60 lines by 80 characters. For the page orientation, the raster scan has not been rotated with the CRT. The line-scan remains horizontal, now the shorter dimension, while the frame-scan remains vertical, now the longer dimension.	The screen filled at the maximum 60 lines, by 80 characters. The choices for number of on-screen lines is 18,20,22,24,26,28,30,36,40,48 or 60.	The screen at 48 lines by 80 characters. The number of lines can be changed manually by pressing CTL+MOVE-UP, CTL+MOVE-DOWN. MOVE-UP, MOVE-DOWN scroll through off-screen lines.
The screen at the common 24 lines by 80 characters.	The screen at the minimum 18 lines, by 80 characters.	Model & serial # labels: monitor unit left, keyboard right.
Interior view of the monitor assembly holding the analog board, and on the left the logic boards removed from the rear case.	The analog board containing the power supply and monitor scanning and video circuitry. This is the later version of the analog board: the power supply and vertical-scan circuitry are changed from the earlier version. This particular instance has also been further modified for a repair, see next photo.	Closer view of the power supply repair. The upside-down IC is a UA1845 (UA3845), replacing a failed NE5561, a now-obsolete switching-supply controller. See schematic for details.
The main logic board, with Z80 processor.	The IO logic board with two UARTS, and battery-backed RAM to store configuration.	Stack assembly of the two logic boards.