NON-IMPACT PRINTING

All About Typewriter Terminals

Members Qf the Qther basic class Qf printers - the nQn-impact units - emplQy variQus electronic and chemical techniques to' product printed images fQrmed by SQlid lines Qr a matrix Qf dots. SQme Qf the nQn-impact printing techniques have eVQlved frQm the develQpment Qf facsimile communicatiQns; Qthers were specifically develQped for use in high-speed printing applicatiQns, where print speeds Qf better than 2000 lines per minute are nQt unCQmmQn, Qr as lQw-cQst alternatives to' impact printing.

The electrothermal (Qr thermal) printing technique is the mQst cQmmQnly used Qf the nQn-impact techniques and is emplQyed in the terminals produced by twO' leading manu-facturers Qf nQn-impact printers, NCR and Texas In-struments.

The ink-jet technique, simultaneQusly develQped by A. B.

Dick and by Teletype CQrpQratiQn for high-speed printing applicatiQns, sprays a stream Qf electrically charged ink drQplets QntQ ordinary paper to' prQduce printed char-acters. Character fQrmatiQn is perfQrmed by electrostatic deflectiQn plates that cQntrol the directiQn Qf the charged ink drQplets, in much the same manner as the electron beam mQvement is cQntrolled within a cathQde ray tube (CRT). The ink-jet technique is expensive (Qver $6,000 per unit) and has a limited market PQtential, as indicated by the small number Qf units delivered by bQth CQm-panies.

AnQther familiar nQn-impact printing technique is the xerographic principle used in the ubiquitQUS Xerox cQpiers. AlthQugh it is a cQmparatively expensive technique, xerQgraphic printing has Qne major advantage Qver mQst Qther nQn-impact techniques: it uses ordinary plain paper. Recently, Xerox CQrporatiQn cQmbined the xerographic principle with cQmputer technQIQgy to' produce a 4000-line-per-minute printer that prints Qn ordinary 8~ by 11 inch paper. The Xerox 1200 CQmputer Printing System is detailed in Report 70D-931-0 1.

t::

REPRODUCTION PROHIBITED OCTOBER 1973

700-010-21e Peripherals

All About Typewriter Terminals

[:> Reliability of most non-impact printers is comparatively high because they have few mechanical parts; 3000 hours or better between failures is not uncommon.

Silence is golden, so it has been said, and there are some quiet environments where the noise of an impact printer simply cannot be tolerated. The virtually silent non-impact printers are especially desirable in these loca-tions.

The non-impact printers' ability to produce only one copy at a time might be a key disadvantage if you normally require several copies. But if you don't mind the ad-ditional time required to run off the needed extra copies on a nearby copying machine, the limitation of one copy may not be detrimental.

USER EXPERIENCE

To access the current level of user satisfaction with type-writer terminals, Datapro Research Corporation con-ducted a survey of users of this equipment in July 1973.

A typewriter terminal survey form was included in the July supplement to DAT APRO 70 and mailed to all subscribers.

By the response cut-off data of September 1, usable responses had been received from 181 users with a total of 6,475 installed terminals. This represents an average of 36 terminals per user - but there was one user with 1,400 of the special-purpose IBM 1980 units and another with 775 IBM 2970-8 teller terminals. Without these two large IBM users, the average terminal usage drops to 24 per responding user.

IBM terminals were the most numerous, with 2,991 of them among 70 reporting users. This is an average of 43 terminals per user, with the average bolstered by the large-quantity users of the IBM 1980 and 2970-8 units noted above. Without these two users, the IBM responses amount to 816 terminals among 68 users, an average of 12 per user. Among the general-purpose IBM "production"

terminals, the popularity leader was the 2741, with 33 reporting users, and the most numerous was the 2740, with 448 installed.

Teletype terminals were the most popular, as expected, with 115 users reporting. They were using 2,583 Teletype terminals among them, for an average of 22 terminals per user. The single most popular and also the most numerous unit was the Teletype Model 33 ASR, with 75 users reporting on their experience with 1,464 of these units, an average of 20 per user.

The survey asked the users to classify their terminals

ac-(2) ease of use, (3) keyboard feel and usability, (4) print quality, (5) hardware reliability, and (6) maintenance serv-ice? The detailed user responses to all these questions are presented in the "Users' Ratings" table on the next page.

To clarify the crucial factor of overall performance, a

"weighted average" or "grade point average" is also reported in the table. That is, the "excellent" answers were totalled and multiplied by 4, the "good" answers totalled and multiplied by 3, and so on. These weighted averages should be considered in the light of the numbers of responses involved in each case; some of the samples are obviously too small to be regarded as conclusive.

Deserving, we think, of special mention are the five terminals that earned a weighted overall performance average of 3.5 or more from at least 5 responding users.

They were: the Anderson-Jacobson 841 (3.5 with 9 respondents), the Computer Devices 1030 (3.6 with 5 respondents), the CTSI Execuport 300 (3.6 with 9 respondents), the Data Products Portacom (3.9 with 7 respondents), and the GE TermiNet 300 (3.5 with 24 respondents ).

To see how the Teletype and IBM terminals compared with those of their numerous competitors, totals of the excellent, good, fair, and poor responses to all six questions were computed for the Teletype units, the IBM 1>

cording to their characteristics, and also asked for re- The futuristic-looking DECwriter, produced by Digital Equipment

11 Corporation, contains an impact nu;trix printer rated at 10, 15, or

sponses - exce ent, good, fair, or poor - to these six 30 characters per second. Available as a communications terminal, questions: How would you rate each type of terminal the DECwriter can also be connected directly to the popular DEC you're using with respect to: (1) overall performance, minicomputers.

700-010-21f

Carterfone (all models) Computer Devices 1030 CTSI Execuport 300 Data Products

All About Typewriter Terminals USERS' RATINGS OF TYPEWRITER TERMINALS

Users' Ratings**

No. of Overall Overall

Ease Keyboard

Print Terminals Performance,

Perform-of Use Feel and

*Only those terminals rated by at least two users are listed here; 28 other terminals were rated by only one user each.

**Ratings are expressed in terms of number of user responses. The legend is E for Excellent, G for Good, F for Fair, and P for Poor.

REPRODUCTION PROHIBITED OCTOBER 1973

700-010-21 9 Peripherals

All About Typewriter Terminals t::> units, and all other makes. The results are tabulated

below; they show little difference among the overall user ratings of the Teletype, IBM, and competitive terminals.

Totalled Responses for Teletype Terminals

Rating No. of Responses % of Total

Excellent 151 23

Good 326 50

Fair 150 23

Poor 23 4

Weighted Average 2.9

Totalled Responses for IBM Tenninals

Rating No. of Responses % of Total

Excellent Good Fair Poor

Weigh ted Average

145 218 57 19 3.1

33 50 13

Totalled Responses for All Other Tenninals Rating No. of Responses . % of Total

Excellent 342 33

Good 482 47

Fair 167 16

Poor 41 4

Weigh ted Average 3.1

TYPEWRITER TERMINAL CHARACTERISTICS

Im Dokument Contents of Volume 2 datopro (Seite 54-57)