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only in^internal ROM and RAM programs. The number of different parts 
is reduced even though the functions performed may be drastically dif 
ferent. This is economically advantageous, even if in some cases some 
processing capacity is wasted. Furthermore, part replacement problems 
are reduced, there are fewer interconnections (which enhances reliability) 
and desirable system alterations can be introduced by simple programming 
firmware changes. 
CONCLUDING REMARKS 
The infiltration of digital techniques into measuring instruments 
and even into consumer products continues unabated. The driving force 
behind its power of penetration is economy, achieved by taming extremely 
high technology and subjecting it to mass production. 
Photogrammetric equipment manufacturers and users have always been 
highly sensitive to economical factors. Sooner or later, therefore, - 
probably soqner - the photogrammetric equipment field is going to be 
invaded by microelectronics and succumb to the technologies that feed 
the invasion. This will entail substantial technological changes, and 
photogrammetric instrument designers must take the lead in becoming 
conversent in electronics. The topics discussed in this paper give an 
idea of what is involved, as seen today. Tomorrow, new concepts may be 
added! To meet their responsibilities, the photogrammetric instrument 
designers must extend their views and work hard to keep up with the rapid 
development of digital technology. Their success in doing so determines 
to what extent the users can reap benefits from the advances essentially 
paid for by other parts of the world economy.