Hi Ellis,
thank you for the information.
I think that it is a masked ROM (64k), too, but I didn´t know that these were made avialable by a 3rd party developer.
The exact text on the back of the module shows: "82494 REV 0 SURVEY 1 of 1 SINGAPORE". This seems to be the standard HP label.
The ROM contains some BASIC-files which are protected. If I could find a way to read them my problem is solved.
The files are named: "INPT, CKSUM0, VAL1, INSECT, SURVEY, CONVRG, TRAV, RESECT, POLTAB, SUBTNS, ALTMTH, GEOUTM, AZDIST, HASUN, HASTAR, TRIANG"
When I start "SURVEY" I get a table to choose the desired algorithm or program. But I am not enough of a surveillance engineer. I only unterstand the AZDIST and GEOUTM programs (by the help of a nice book about field surveillance techniques) but the parameters of the other programs are unknown.
Best regards
Stefan