INMC 80 News


June/July/August 1980, Issue 1

Page 28 of 48

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.


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. ____ ___.

This is an OCR’d version of the scanned page and likely contains recognition errors.

Page 28 of 48