The problems of multiple specification languages for multiple architec
tures are discussed. It is concluded that an architectural semantics i
s of practical value in ensuring consistent and effective development
of specifications. The approach is discussed in general and by example
s, concentrating mainly on an architectural semantics for Open Systems
Interconnection in relation to ESTELLE, LOTOS and SDL. It is shown ho
w an architectural semantics can be realised using a library of specif
ication templates, allowing the specifier to work at a higher, more ar
chitectural level. Some LOTOS templates are discussed, mainly for Open
Systems Interconnection. (C) 1997 Elsevier Science B.V.