It is surprising to see that over 1 year after the introduction of the first add-on keyboard for the Spectrum, a flood of new keyboards are suddenly appearing on the market. Although an expensive extra, the keyboards enable many owners to use their Spectrum for business applications. Certainly the major deficiency of the Spectrum is its moving keyboard, which is quite an improvement over the ZX81 but still miles away from the full travel typewriter style keyboard of its competitors. Added to this the multi-role, single stroke per function keys have been a constant source of argument as to whether they are a merit or deficiency. The aftermarket keyboard should correct all these deficiencies and upgrade the Spectrum to a more serious home computer.
At first glance the size of the keyboard enclosure suggests a lot of hidden extras, but it soon becomes apparent that the only reason for the Cadillac proportions is the restricted choice of low cost standard keyboard enclosures on the market. The enclosure size tends to dwarf the actual key cluster. The white and grey keytops are certainly the best seen on any Spectrum keyboard with excellent legends using the original colours for extended, symbol and caps shift mode functions. The key cluster has a moulded shape with the front row tilted and slightly projected which allows easier reading of the front row extended mode functions such as Beep, Ink, Paper etc.
The key action usually generates a lot of controversy amongst users, but from my own personal experience I found the action fairly light and giving a good feedback, although just a little bit soggy. Probably a very fast touch typist would find this effect would slow down his or her typing speed, but I should think for the average user the action is perfectly alright. The slightly soggy feel is in fact the only give away clue, that the owner hasn’t escaped the membrane type keyswitch however refined it may be. The switching action is generated by the collapse of a rubber membrane cup with a graphite contact which bridges two interleaved tracks on the printed circuit board. This gives, in combination with the keytop plunger, a nicely balanced and smooth travel. It may be worth pointing out that nearly all low cost home computers feature similar membrane type keyswitch mechanisms (including the QL), as this allows a tremendous cost saving compared to the orthodox keyswitches.
Another interesting feature not apparent to the user is the technology of the printed circuit board, which is not through hole plated as usual, but boasts similar techniques as used with thick film hybrids with silk-screened conductive ink tracks running over the copper tracks of the printed circuit board.
The keyboard features a full length spacebar, a fake caps lock (cap shift and caps lock have to be pressed combined) and a separate numeric keypad with a further cap shift key for the oddly positioned cursor keys in the numeric pad. The layout proves to be a bit of a disappointment as the only benefits are the full-length spacebar and the numeric keypad. It would have been nice to include an extension mode key, stop and comma keys and a cursor cluster all accessible with a single stroke. Nevertheless the layout is practicable and because it is equivalent to the original, the Spectrum owner will instantly feel at home with it.
The installation represents no problems. The Spectrum printed circuit board is fixed via 4 screws, nuts, nylon washers and counternuts onto the plastic vacuum-formed base of the keyboard, which is very flimsy and bows and twists in all directions until fixed to the solid enclosure main body. The ribbon cables of the keyboard plug into the usual sockets of the pcb and that concludes the easy set-up procedure. There is no provision to fit any other add-on inside the case, but the ZX Interface 1 may be connected from the outside and will come to rest underneath the keyboard case giving it an improved tilt which provides a better typing position. An extension cable is however required for connecting up the microdrive unit to the Interface 1 due to the extended dimensions of the keyboard enclosure.
The LO PROFILE provides the Spectrum with a good low profile, full travel keyboard. The keys have a very legible annotation and provide a good feel when typing. It fails however to provide extra benefits such as single stroke extended mode, punctuation and sensible cursor keys. Here the Fuller, Transform and Saga 2 Crusader keyboards definitely score points.
Add-ons may be connected as usual to the extension bus, but no provision is made to fit them inside the keyboard case such as with the DK’Tronics unit, where the ZX Interface 1 and power supply all fit inside the cavernous case. But where the DK’Tronics keyboard is enormously bulky and unhandy to use because of its very high profile, the Advance Memory Products LO PROFILE is exactly what it says, low profile, even if somewhat expansive in respect of required desk top surface.