1 The strict observance of the specifications for standardized international signalling and switching equipment is of the utmost importance in the manufacture and operation of the equipment. Hence these specifications are obligatory except where it is explicitly stipulated to the contrary.
The values given in Fascicles VI.1 to VI.14 are imperative and must be met under normal service
conditions.
2 The Questions entrusted to each Study Group for the Study Period 1989-1992 can be found in Contribution No. 1 to that Study Group.
3 In this Fascicle, the expression ?Administration? is used for shortness to indicate both a telecommunication Administration and a recognized private operating agency.
ITU-T FASCICLE VI.4-1989 history
1989ITU-T FASCICLE VI.4-1989 Specifications of Signalling Systems R1 and R2 Recommendations Q.310 - Q.490 (Study Group XI)