Describes a method for mapping ETSI PDH 2 048 kb/s, 8 448 kb/s, 34 368 kb/s and 139 264 kb/s and ANSI PDH 1 544 kb/s, 6 312 kb/s, 44 736 kb/s and 139 264 kb/s signals over DTM channels; also specifies the characteristics of critical parameters for mapping ETSI PDH signals 2 048 kb/s, 8 448 kb/s, 34 368 kb/s and 139 264 kb/s and ANSI PDH 1 544 kb/s, 6 312 kb/s, 44 736 kb/s and 139 264 kb/s over DTM channels;