EASY-TO-USE PRINTER LINK

Kempston Micro-Electronics has produced a Centronics printer interface which plugs on the back of the Spectrum. There is nothing spectacular in the box as it is an 8255 chip used as a port to access the printer cable.

The printer cable is a full 35-way type and is about one metre long. The plug at the end which fits on the printer seemed a little too thick to put the securing clips around but it was a tight fit in the socket.

All the hard work is done in 650 bytes of machine code stored above RAMTOP; a different program is provided for each computer. That may seem a great deal but the accompanying Basic program allows you to specify a number of options on the printer. Once those options are set, the program will save the machine code only to allow you to use all the rest of the RAM yourself.

Line length, changing the character codes for individual characters, special features such as the line feed and carriage return, can be set in software. All those commands affect only LPRINT and LLIST as COPY is ignored.

Any of the options can be ignored by pressing ENTER in response to the question. In that way a printing routine can be personalised and if, say, the line length is limited to 32, LLIST would produce a duplicate of that listed on the screen.

Hilderbay, the company which produced the software, must be congratulated on providing a fine, easy-to-use piece of software.

The only way to COPY a screen suggested in the instructions is to use the Basic Point command in a loop to assemble the required graphic bytes to put out to the printer. That is useful but slow and the routine applies only to Epson printers. Looking through the printer manual is the only answer if you do not have one of those.

A machine code program for at least two of the popular printers to simulate, if not use the COPY command, would have been useful. That seems preferable to the LPRINT, is it allows you control of the printer with as much ease as possible.

The printer interface costs £45 and is available from Kempston Microelectronics, 180a Bedford Road, Kempston, Bedford MK42 8BL.

INTERFACE HAS USEFUL FEATURES

New from Kempston Electronics is the Model E Centronics interface for the Spectrum. It contains an EPROM which enables it, on power-up, to direct the commands LPRINT and LLIST direct to the printer without the need for additional software. Also built into the EPROM are routines which allow the use of COPY for the Epson and Seikosha ranges of printers.

Housed in the standard Kempston case, the interface plugs into the user port of the Spectrum and is complete with a cable to connect to the printer. The interface is dead-ended in that it does not have a through port for other add-ons; that may be a problem if you want to use it at the same time as the Kempston joystick interface or any other dead-ended device. A problem which may arise with full-size keyboards is that the case is shaped with a lip to fit on top of the standard Spectrum. The lip may prevent the case fitting snugly.

Inside the case is a 2K EPROM which houses the printer software and a handful of chips which detect when the Spectrum is using the LPRINT, LIIST and COPY commands. It does that with the COPY command by monitoring an address and when the Spectrum uses it to do a COPY the interface takes over and directs output to the printer.

Using the interface is very simple. If only text is to be printed, no setting-up is needed, apart from POKEing an address with the number of columns required if that is other than the default setting of 80. That address is one of the unused ones in the system variables area.

To use the COPY command the interface must be set up for your type of printer. By entering as a direct command COPY:REM? the interface displays a menu page which shows its current status. You can then set it up for the Epson range, Seikosha 100 or 250 printers, or add your own routines.

Once you have set it up in that way any user-defined characters or graphics characters which appear in a listing will be printed as shown on the screen. An annoying feature is that those characters are wider than normal characters and make the listing appear untidy.

For computer artists there is an enlarged setting. When that is turned on COPY will produce a double-sized copy, about 180mm. x 145mm. on an Epson, suitable for hanging on the wall. Other settings are available to control the tokens, escape characters and automatic line feeds.

At £55 inc. the interface is by no means inexpensive - but it contains many useful features.

Details from Kempston Micro Electronics Lid, Unit 30, Singer Way, Woburn Road Industrial Estate, Kempston, Redford MK42 7AF. Tel: 0234-856633.

PRINTING ON A BUDGET

For most of us all we require from a printer is that it will cope with our listings and do a reasonably legible job of printing out wordprocessed documents. Curiously enough speed is rarely nominated as a highly significant factor.

In this survey we have deliberately limited ourselves in two ways. First, none of the printers here costs more than £175. Second, all of them are fairly widely available either through high street chain stores or the larger specialist shops.

The idea is to give a simple guide to relatively straightforward printers for those with a limited budget.

All the printers here will do the job, but any considerations that may be a particular plus or minus are highlighted.

CHOOSING A PRINTER - VITAL QUESTIONS

Ask yourself the following questions:

Q: Will I be using it for formal letters?
A: You probably need a printer with a near letter-quality (NLQ) mode or equivalent

Q: Will I be using it with a program or programs where a high degree of Epson compatibility could be important or particularly useful?
A: Epson compatibility can be significant because some programs have special features that will only work using Epson character code conventions eg screen dumps

Q: Does speed matter?
A: it probably won't unless you intend using it quite intensively for business

Q: Serial or parallel?
A: Seemingly obvious but many people don't realise that if you already have an Interface One you already have a serial interface suitable for connection to some of the printers here. You may not want to buy a new one. Most commercial Spectrum interfaces however, are Centronics ie parallel as are the majority (marginally) of printers

Q: Normal paper?
A: Thermal printers are often cheap and quite effective but they require special paper which, aside from having to be bought specially, may not be suitable for letters

Q:Special ribbon?
A: Some printers use unconventional kinds of print ribbon that you may find difficult to replace except from the original manufacturers. This may be very inconvenient

Q: Dot-matrix versus daisywheel - does it matter?
A: A simple generalisation: even a simple daisywheel will almost certainly have a better text print quality than most dot matrix (even those with NLQ). But a daisywheel will probably be slower and it definitely won't be able to cope with any sort of graphic dumps. If you want graphics you must choose dot-matrix.

SHOP AROUND

There are good bargains to be found if you know where to look and don't mind having a model that has been superceded (which usually only means slightly improved and put in a different box).

The following printers are available at various prices. We indicate a target price found in a weary trek up the Tottenham Court Road. You may be able to do better by keeping your eyes open.

Brother HR-5 - an early printer from Brother with standard dot-matrix features. Good enough for most purposes. Target price: £69.99

Citizen 1200 - good all-round dot-matrix from a company fairly new to the market. Tractor Feed as standard. Target price: £169

Seikosha GP500A - bulky but effective dot-matrix. Target price: £115.95

Centronics GLP printer - recently superceded, neat little dot-matrix. Target price: £125

Quendata Daisywheel - unusual in that it's a daisywheel. Slow (18cps) but neat print. Target price: £135

Sinwa CPA-80 - 80-column dot-matrix with NLQ. Target price: £145

Juki 6000 - another daisywheel. Slow (10cps) but sturdy and reliable. Target price: £170

Star Gemini 10X - dot-matrix with impressive spec (120cps). Includes tractor feed and is Epson compatible. Target price: £150

Mannesann Tally MP80 + - good general purpose dot-matrix. Target price: £175

Epson P40 - small thermal, small-width printer. OK for listings. Target price £45.

Make/Model: Star STX-80
Typical Price: £79
Print speed (char/sec): 60
Print quality: Average dot-matrix
Interface: Centronics
Printing style: Thermal
Founts: Standard ASCII/International/Block graphics
Other Features: Programmable line spacing, excellent manual
Verdict: A very high quality thermal printer, which is to say that it has lots of special features but it still isn't suitable for any but the most informal letters. It uses a continuous roll of special thermal paper. Imagine a Rolls Royce version of the ZX Printer and you'll have a pretty good idea of what to expect.

If you can accept using special paper then the STX-80 is really very good value for money. It can do most of the clever things Epsons can, including print at different heights and widths. It also has various special character sets accessed through dip switches which give, amongst other things, special graphic shapes and the possibility of customising your own fount designs.

Make/Model: Saga LTR-1
Typical Price: £139.95
Print speed (char/sec): 12
Print quality: Letter quality
Interface: Centronics
Printing style: Daisywheel
Founts: Elite only
Other Features: Simple RS232 interface included
Verdict: A very cheap printer with quite a few unusual features. It uses a special form of daisywheel printing in which an embossed roller is linked via an ink roller. The end result is as good as most daisy-wheel printers. It has no special features like international character sets or tractor feed but can nevertheless be recommended where print quality has a fairly high priority but other factors, like speed, are unimportant.

Make/Model: Star Delta 10
Typical Price: £161.50 (available at this price from Flightpath, 43 Hithermoor, Staines, Middx TW19 6AH)
Print speed (char/sec): 160 (10 & 12 chars/inch), 137 (17 chars/inch)
Print quality: Good dot-matrix
Interface: Centronics & serial RS232
Printing style: Dot-matrix 9x9 pin
Founts: Various
Other Features:Wealth of other options and facilities accessible via control codes.
Verdict: An impressive dot-matrix machine - it's an absolute bargain if you can get hold of it. It is a full featured dot-matrix with external controls for Line-feed, Form-feed, On/Off line etc. A large number of alternative character sets include block shapes and international letters, customised character set facilities which can be downloaded into special printer Ram, variable line settings and so on. There are three density (characters per inch) settings. Print quality is certainly good enough for almost all purposes although there is not an NLQ setting as such. The printer has both RS232 serial and parallel Centronics interface ports and easily accessible dip switches. The manual is excellent.

Make/Model: Epson P-80
Typical Price: £
Print speed (char/sec):
Print quality:
Interface:
Printing style:
Founts:
Other Features:
Verdict: An unusual printer. Thermal, but it prints on a special kind of paper that looks to all appearances like conventional A4. If you don't mind being locked into buying the special paper this could be a good option. It is very neatly designed. The biggest advantage is that, being an Epson, it has certain control code conventions that should make it easy to use with most commercial software. A serial interface version is also available and the printer can also be powered by batteries.

Make/Model: Brother M1009
Typical Price: £
Print speed (char/sec):
Print quality:
Interface:
Printing style:
Founts:
Other Features:
Verdict: Extremely popular low-cost dot-matrix printer, quite well supported by commercial software. Although it doesn't specifically have an NLQ mode it is certainly capable of a print quality more than adequate for most purposes. A large number of special features include various print densities, tab settings, emphasised print, double-width and many other print options. Recommended but at the top of our price range.

INTERFACES

There are two kinds of interface which will enable you to connect your spectrum or QL to a printer.

Make sure you choose the right sort for your printer. For practical purposes there is no special advantage between serial or parallel (RS232 or Centronics) interfaces. An RS232 interface may be more useful for other things - like modems - but Centronics is the rather more common standard.

SPECTRUM
SERIAL (RS232)

Interface One - Sinclair's own.

Networking and Microdrive interfacing as well. The most common RS232 used in commercial programs.

PARALLEL (CENTRONICS)

Kempston - a sophisticated Centronics interface which has the advantage of having all the customising/driving software on Rom ie, there is nothing to load in. Supported by almost all commercial software using printers

Tasman - A neat interface with driving software on tape. Well supported. The standard interface for Tasword wordprocessor and associated packages

Euroelectronics ZXLPrint III - well supported and also provides an RS232 port. No additional software is needed and on quite a wide range of printers standard LPrlnt List and Copy commands will work

S-Print intended specifically for the Kempston Centronics Spectrum 128

QL
Comes with RS232 as standard

PARALLEL (CENTRONICS)

Miracle Centronics interface - one of the first and so quite well supported. No additional software needed

Q-Print - similar to the above. Does not require driving software

Spectrum
£39.95
Centronics Interface

Compatible with just about anything you can stick on a Spectrum, this new interface from Kempston comes with a metre of ribbon cable and is styled like the new Speccy +. The software in Eprom supports LPrint, LList and Copy commands.

GETTING INTO PRINT

Good as it is for the price, many users are bound to be disappointed with the output from Sinclair Research's own printing device. For those toying with the idea of upgrading their Spectrum system with a professional printer, Henry Budgett takes an in-depth look at the technology involved and the plethora of interface devices now available.

Regardless of what one actually thinks about Sinclair Research's ZX Printer, it's impossible to ignore the fact that it really does work. For the price and performance that it offers there's no equal anywhere. But despite that, there are users who need something a little more professional. Software houses developing programs, small businesses using the ZX Spectrum or just a serious user who demands something better than a sheet of aluminised paper that is, at best, just legible after a few days' handling.

We're fortunate in having a number of commercially available interface units that allow the ZX Spectrum to be connected to the growing range of low-cost printers. In the main, these units convert the signals provided on the expansion connector into those which conform to the industry standard Centronics interface. There are two stages to this conversion: that of altering the electrical characteristics of the output from the ZX Spectrum and that of converting the character codes from Sinclair Research's own internal format to true ASCII.

The alterations to the electrical signals are handled in a variety of ways by the interfaces reviewed here; some use very sophisticated chips to handle the work, others tackle the task by using more of the simple ICs. Only one of the interfaces in this review offered the possibility of connecting to a serial printer but, in theory at least, the problems involved are tackled in much the same way.

All the interfaces were supplied with software drivers of one sort or another (see the individual panels for further details) and in general, these all work by intercepting the ZX Spectrum's printer routine vector. This is the location in memory that stores the address of the routine which controls data being sent to the printer by LLIST and LPRINT. By changing this address to that of the new driver all the data is re-routed through one of the OUT ports to the interface. On their way, each of the characters passes through a 'code converting' routine held somewhere in memory. While the normal alphanumeric codes closely follow the standard ASCII set, all the control codes, predefined graphics and Basic tokens must be intercepted. In the case of the tokens, these are converted back into strings of ASCII letters before being listed. Because many of the currently available printers use sequences of control codes to change character fonts or to select graphics, provision must also be made to allow these codes to be sent without being trapped.

The test equipment to which the various interfaces were connected comprised a Tandy CGP-115 four-pen plotter printer and an Epson FX-80 dot matrix printer. Unfortunately, the Epson turned out to be 'Dead on Arrival' and the author's Apple Dot Matrix Printer was substituted. As this printer is based on a TEC chassis, it proved impossible to check the graphics dump facilities on all but one of the interfaces. However, there is no evidence to suggest that the software provided wouldn't operate correctly with the appropriate hardware and indeed, the Kempston interface unit has been seen elsewhere to function perfectly with both the RX-80 and FX-80 printers.

Hardware: A very neat and specially designed casing houses the single printed circuit board. Featuring just two ICs (an 8255 and 4071) the unit is constructed from high quality components and mounts vertically behind the ZX Spectrum, contact being made through a gold-plated edge connector. No provision has been made for other units to cascade from the rear of the interface. The interface cable is detachable but not keyed at the interface end; it might therefore be possible to connect it upside down.

Manual: The accompanying documentation consists of just four pages, A5 sized. All the necessary information to attach and operate the unit is given although the quality of the photocopy is poor in places.

Software: Four programs are provided on cassette to support the interface and all reside in the printer buffer when loaded. The main program is a simple text-only driver which supports LLIST, LPRINT, PRINT AT, TAB AND ','. All the standard ASCII characters are coped with and all keywords are de-tokenised; control codes can be sent by LPRINTing the appropriate CHR$(x). In addition to these standard features the software supports a TEXT COPY, called by RANDOMIZE USR 23370, and allows the number of characters per line to be set. Also included, and very useful too, is the facility to enable or disable the Line Feed character after each Carriage Return.

Kempston also provides, on the same tape, three high resolution copy programs. These effectively replace the text driver's TEXT COPY with a screen graphics copy, all other facilities remaining the same. The first program is for all the standard Epson printers, but programs for the Seikosha GP80/GP100 and the Seikosha GP250X are also provided.

Price: £45.00 all inclusive.

Summary: An excellent product and one which, in a commercial software environment, has proved to be totally reliable. The instructions are short and sweet, no problems would be encountered by even the newest of newcomers.

OVERALL SUMMARY

Of the three standard units - Kempston, ADS and LPRINT Mk II - the latter inherently has the advantage of on-board software, giving it greater speed and more flexibility. Between the other two the ADS is slightly the neater but the Kempston is supplied with a better range of driver software and virtually every- thing works with it directly.

The two 'up-market' units both have advantages in their own ways. For serial printers there is no option but to choose the Morex unit. It offers parallel as well and comes complete with an excellent manual; if pushed, it probably represents the 'Best Buy'. It's a shame about the packaging - fit a nice box around it and you'd have a real winner.

The Hilderbay unit stands or falls on its usage. If there is a need in your life for a printer buffer - and you already have a ZX Spectrum - then this interface will satisfy both requirements. It's also rather cheaper than having to fork out £230 for a 64K printer buffer! As a standard interface it offers nothing special, apart from direct compatibility with all of Hilderbay's software.

There are other printer interfaces around - for instance, Softest offer one especially for the Tandy CGP-115. However, as it's a serial-only interface and all the others seem to drive the device quite well, I'm not sure about its value. Unfortunately, the promised review unit failed to appear by the deadline for this survey so no further comment is possible.

The interface you choose should really reflect the uses to which it is going to be put. If all you want is a simple-to-use means of getting a proper printout then the ADS, LPRINT Mk II and Kempston units offer just what you are looking for, provided that the driving software is available. More sophisticated users will find the Morex unit well worth a look and those with other computers to support will find the Hilderbay device attractive from the printer spooler viewpoint.

HARDWARE WORLD

With ever-increasing amounts of peripherals available for Sinclair computers, users are finding it more and more difficult to know what to buy. We present a buyer's guide to joysticks, keyboard and printers and review the best of the rest from the 1984 add-on market.

The last year has brought about a vast change in the sort of add-ons available for the Sinclair machines. Many are technically brilliant while some would have made Heath Robinson blush. There are few add-ons still being produced for the ZX81, with even fewer new ones, but there has been an avalanche of Spectrum designs, and the start of what promises to be an interesting range for the QL.

The most popular areas of interest - printers, joysticks and keyboards - are dealt with in separate sections but there have been some very innovative designs produced in other areas.

KEMPSTON INTERFACE

Now that the Sinclair ZX printer has been discontinued, interfaces for full-size printers are becoming sought-after. One of the best of these for the Spectrum is the Kempston Electronics model E. The interface contains an EPROM that enables it, on power up, to direct the commands LPRINT and LLIST direct to the printer without the need for additional software. Also built into the EPROM are routines that allow the use of COPY for the Epsom and Seikosha range of printers.

It is housed in the standard Kempston case, plugs into the user port of the Spectrum, and is supplied complete with a cable to connect to the printer. The interface is dead-ended - that is it does not have a through port for other add-ons - and that may be a problem if you want to use it at the same time as the Kempston joystick interface or any other dead-ended device.

Using the interface is very simple. If text only is to be printed then no setting up is needed, apart from POKEing an address with the number of columns required if that is other than the default setting of 80. That address is one of the unused ones in the system variables area.

To use the COPY command the interface must be set up for your type of printer. If you enter the direct command COPY:REM? the interface displays a menu page which shows its current status. You can then set it up for the Epsom range, Seikosha 100/250 printers or add your own routines.

Once you have set it up in this way any user-defined characters or graphic characters that appear in a listing will be printed as shown on the screen. For computer artists there is an enlarged setting which produces a double size COPY. Other settings are available to control the tokens, escape characters, and automatic linefeeds. The interface is by no means cheap but does contain many useful features.

Kempston Printer Interface Model E, £55.00 inc. from Kempston Micro Electronics Ltd, Unit 30, Singer Way, Woburn Road Industrial Estate, Kempston, Bedford MK42 7AF. Tel: (0234) 856633.