Review of Port Probe and Key Pads from Bits & P.c’s.
by R. O’Farrell
The Port Probe is a small single sided P.C. board 4" x 3", supplied
drilled and tinned, which holds 4 i.c.s, an 8 position DIL switch, 9
LEDs and four push button switches. The i.c.s are supplied with
sockets, and are configured to make up a clock, whose frequency can be
altered by a preset within limits (1 cycle every 0.5 sec to 1 cycle
every 3 secs approx). This clock can be started and stopped by two of
the push buttons, and is fed to a timing chain. Selected outputs from
this chain can be fed to a PIO port (16 pin dil connector supplied) and
the workings of this complex and mysterious item explored in full. The
other two switches on the probe are to reset the counter and to
handshake with the port. It is well documented with two sample programs
supplied to get you started. At the price of 11.20 I would regard it as
a must for any NI/N2 owner.
The control and HEX keyboards consist of a bank of keys on each side of
an island of i.c.s. Depending on whether you order one or the other or
both, so you get the centre island, and one or the other bank of keys.
The keys are supplied with proper keytops, very like the Nascom
keyboard. If you have changed an N1 to Nas Sys, then the control keypad
allows all the cursor movement characters to be accessed easily – much
easier than remembering how to get say ‘control T’. Again, well
documented and socketed. The extension board takes the umbilical from
the Nascom board, and in turn plugs into the Nascom Main board. For a
INascom 1 running under Nas Sys, the control pad is essential, the HEX
pad not so important. One slight problem on mine, a tendancy for
certain characters to repeat. This I cured by swapping certain of the
i.c.s about. I feel it is due to the Flipflop connected gates on the
Nascom Keyboard re-flipping because of echoes on the line, and perhaps
if it occurs often a veroboard mounted line driver near the N1 keyboard
might cure it. All in all, two most satisfactory purchases. I strongly
recommend the port probe to all N1/N2 owners, and the control section
of the extended keyboard to N1’s running under Nas Sys. The control
keypad costs 23.10, the HEX keypad 30.10, and both together 37.25.
3M PERSONAL COMPUTING CASSETTES.
by D. Brough
3M have recently introduced C10 & C30 cassetts designed for personal
computer users. Several people have had very good results with the
C30’s up to at least 1200 baud both on NASCOMs and SORCERORs. One of
the test tapes did have some creases which caused dropouts but this was
replaced without question. The tapes at present have’ transparent
leaders but this may be changed soon. Prices are:- (Post Free).
C10 – 64p incl VAT C30 – 67p incl VAT
Contact 3M at 3M (UK) Ltd., P.O. Box 1, Bracknell, Berkshire. ____ ___.