Terminals
Disc drive
Two c.r.t, terminals have been added to Hewlett Packard's line of c o m p u t e r peripherals. The HP 2 6 1 5 A is a teleprinter compatible terminal operating at higher speeds than the currently offered HP 2 6 0 0 A terminal. The more powerful HP 2 6 1 6 A terminal has, in addition, page-mode operation and offline editing. The HP 2 6 1 6 A allows transmission of up to 2048 characters at a time. Up to 256 lines may be stored while a maxim u m display of 26 lines of 80 characters can be shown. Page, line and character editing minimize data-entry errors and subsequent re-transmission. A n o t h e r way to shorten transmission time is to use the unit's p r o t e c t e d fields to create forms for data-entry. When the forms are c o m p l e t e d only the entered data is transmitted to the c.p.u. The 2 6 t 6 A offers asynchronous data transfer with switch selected baud rates of 1 1 0 - 9 6 0 0 and the unit may be interfaced to the Hewlett Packard series 2100 computers. A hardcopy unit can be c o n n e c t e d to terminals. The 2 6 1 6 A also includes a 12in diagonal display with blink and reverse video, tabulator, a 106-key detachable keyboard, 96 upper and lower case characters, and eight special-function keys. The unit also c o n f o r m s to ANSI code. The liP 2 6 1 5 A terminal is an asynchronous unit that can be o p e r a t e d at transmission rates up to 9 6 0 0 baud. The terminal uses a 12-inch diagonal display having a capacity of 2000 characters. Twenty-five lines of 80 upper-case characters can be displayed. The terminal features a 53 key teleprinter keyboard. (Hewlett Packard
The Trident family of removable-pack disc drives use 384 track per inch technology with up to 822 cylinders and 806 k b y t e per second data transfer rate. Each m e m b e r of the range provides random access storage available in 25, 50 and 80 Mbyte capacities at a low cost-per-byte ratio The storage m e d i u m is a five-high disc pack m o u n t e d on a 3330 type spindle to provide five surfaccs for data recording and a sixth surface to a c c o m m o d a t e servo track positioning. Each drive includes a c o m p l e t e air flow system, power supply, control and data electronics plus read/write timing synchronization. (Century Data
Division, CalCornp Ltd, AMP House, Dingwall Road, Croydon, England CR9 2NX. Tel: 01-681 0261)
The Trident disc drive uses 3 3 3 0 typ~ teebnology to give a competitive cost per-byte ratio
Mini-grid digitizer
has produced a device that is said to be cheap to produce, reliable in operation and requiring no preventative maintenance o t h e r than the normal periodic adjustment of the associated e q u i p ment, such as paper tape punch. The digitizer has the advantage of absolute measurement which ensures that the origin is not lost when the viewer is lifted. The mini-grid can be obtained in one of three working areas namely 0.28 m x 0.28 m, 0.5 m x 0.5 m and 0.9 m x 1.22 m. The smallest size operates as a parallel T T L signal data tablet for a m i n i c o m p u t e r while the largest one is c o m p l e t e with the ASCI 1 keyboard, point and stream digitizing modes, card punch interface and a software support package. (D-mac Ltd, Sbafiesbury
Ltd, 224 Bath Road, Slough, Bucks, SL1 4DS. Teh Slough 33341)
The D-mac range has been added to with the introduction of the Mini-grid electronic digitizer. This electronic digitizer is suitable for processing strip charts, seismic traces, t o w n plans, design sketches and all types of graphical data with 0.00025 m resolution, accurate to +1 digit. Mini-grid uses the principle of magnetostriction normally associated with delay lines and filters. Pulses are applied to the x and y transmission wires at two adjacent edges of the digitizing board. These pulses cause strain waves to be propagated through a mesh incorporated in the board. The signal is d e t e c t e d by a receiving coil in the digitizing cursor and the distance is f o u n d digitally f r o m the elapsed time in each axis. This simplified digitizer construction
The 2615A c.r.t, terminal
The Mini-grid digitizer sbowing a trace in position ready ]or processing
66
Street, H~gb Wycombe, Bucks, England flP11 2NA. Tel: tfigb Wycon~be (0494) .?464 I)
COMPUTER A l l ) E l ) DESIGN