Talbot's Dialtex 4 bears more than a passing resemblance to the Epson PX-8. An added extra is a built-in word processor that is just a little half-hearted, says Barry Thomas

Inside the Dialtex 4 hides an Epson C/PM machine, fairly minimally disguised by having the word processing ROM of another company, Talbot Computers, built in. At first sight, it seems a little old fashioned: the micro cassette drive and the smallish screen are more reminiscent of Epson's HX-20 than one of the new breed of laphelds such as the Data General One.

The CPU is a CMOS Z80 with a clock speed of 3.68 MHz. A 7508, 4-bit slave CPU controls keyboard input and such items as the power supply.

A dazzling array of physical features has been crammed onto the Dialtex. The keyboard's 72 keys include five function keys plus five more with the shift key. Next to these are four keys labelled Stop, Esc, Pause and Help/System. These are all calculator style keys with a slight click action. The other keys are full travel, full-size typewriter fashion.

The 40 character by 8-line liquid crystal display tilts about 35 degrees, after pressing a button at the back, but lacks some of the clarity of the NEC and Tandy models. However, a contrast control on the right side of the casing means most lighting situations can be catered for.

On the review model, to the right of the screen was a micro cassette drive with an eject button and two LEDs marked Free and Rec(ord). The standard machine comes with a dummy cartridge, which can be fitted with a circuit board, for specialised applications, by the user. This whole corner of the micro can be removed and replaced with a modem, RAM module or whatever else Talbot may dream up.

The cassette drive is accessed by the system as drive H:, so data and programs may be written to or read from the drive as if it were another RAM drive - except of course that access is sequential, not random.

The right side of the casing features a tiny Reset button, recessed into the plastic. It's in a handy position, but could not be pressed by accident. Pressing it performs a warm reset, so if you are in the word processing program for instance, your current file would be lost, but the RAM contents would be safe.

Next to it is the thumbwheel which adjusts the contrast of the LCD screen. Then comes the power switch, followed by a jack socket where a bar code reader can be fitted as well as an external speaker socket.

The rear of the casing has two flip-up legs to make the typing angle just a little less flat. Grouped closely together are three mini DIN sockets; Cassette, Serial and RS232C. These are followed by a Centronics printer socket and the input for a mains adaptor. You'd need this after about 15-20 hours use. When power in the alkaline batteries becomes dangerously low, the screen clears and a 'charge battery' appears, and so long as the mains/transformer is then plugged in, normal use can continue.

The left side of the machine looks bare, but a plastic cover hides the 50 pin expansion bus. The full pin out of this port is given in the operating manual.

The base of the micro is also far from featureless. For a start there is a sliding catch and a finger grip for easy removal of the micro cassette drive. And then there are two flat, enticingly removable panels.

One allows access to an alkaline battery pack, which may be replaced with ordinary dry cells. The other panel lifts off to reveal three ROM sockets, protected by an aluminised card shield, a cold reset button and a set of dip switches.

The DIP switches alongside the ROM chips are used to assign the type of printer, the type of device operated by the LST: command and the type of keyboard in use. The standard keyboard is QWERTY, but may be replaced with a calculator style version.

This optional keyboard, known as the Item keyboard, falls neatly into two banks of keys. All but one of the 32 keys in the left-hand set are user-definable - the one exception is the Shift key. These may be configured to input different strings of characters when pressed, so that the computer may be used for specialised tasks. A set of overlays sits neatly behind a transparent keyboard surround on which the legends for each key can be printed. The right-hand bank of 23 keys contains the numerals, arithmetic functions and a Return key.

The 265 page operating manual, stamped 'Preliminary', would shame many a micro manufacturer, such is the professional approach of Epson. Throughout, the computer is refered to as the PX-4, thus further betraying the excellent parentage of the micro. An excellent first chapter puts the machine into its place in the Epson family of peripherals and outlines what CP/M is, with a list of commands. The following chapters are just as comprehensive apart from missing an index.

The Basic manual is equally impressive. All the commands available to this implementation of Microsoft Basic are listed with examples of their use within Basic programs.

The screen display, at 40 characters by eight lines, is line a window on a larger screen of up to 50 lines of 80 characters. So, in theory, genuine CP/M software can run. The screen is not as easy as some to read, even with its adjustable angle and contrast.

A set of graphics commands includes PSET, PRESET, LINE and POINT. One feature of the graphics capability which differs from the less powerful laphelds is that graphics scroll with other information on the screen.

Other useful commands include CHAIN to load and run another Basic program without losing values of variables from the first; some disk handling commands and even a gorgeous little command called OPTION COUNTRY, where you can change the default character set from within Basic.

Lesser laphelds tend to have some form of text formatter built into the ROM, so to get the text out into a decent document form, a text outputter is needed. The Dialtex contains a ROM chip bearing a word processing program (Intext). Not only does it handle the text as it is input, but also as it is formatted out to a printer.

The built-in communications option allows you to access the RS232 port at up to 38,400 baud. Not in the least bit slow, it works out at about 3.8K bytes of information per second. Any parameters for transmission can be set and saved to RAM as a default setting. Or they may be individually set up to the user's specifications.

Selection from the Intext menu is made with one keypress. E(dit) takes you straight into a blank document. The screen will be either a straight 40 x 8 line version, or the screen may be used as a window onto a screen of up to 80 x 50 lines; L(oad) loads a text file from the RAM disk into memory ready for editing; with P(rint) you can set the line length, page depth, bottom margins and so on, but a header or footer texts and dot commands are out. In fact, the word processor, the only part of the system contributed by Talbot Computers, is the weakest area. Customary features such as block insert and delete are allowed, but the major downfall is the outputting of test.

If this sounds like your sort of micro, you will not be disappointed. However, if the word processor ROM is low on your list of priorities, remember you don't have to buy the machine from Talbot.