clock time 208 to the next sync slave 212 in step 102 the sync slave 212 accepts the clock time 208 sent by the time sync master 200 as its own local system time 214 and derives its operating clock 216 from the adjusted time clock 214 in step 106 the sync slave 212 forwards the clock time 208 communicated by the time sync master 200 unchanged to the next sync slave 218 by a synchronization message 206 in step 110 the sync slave 218 likewise accepts the clock time 208 initially sent by the time sync master 200 as its own local system time 220 the sync slave 218 determines its operating clock 222 from said adjusted local system time in step 112 in step 114 the sync slave 218 forwards the clock time 208 unchanged to the next sync slave 224 by means of a synchronization message 206 in step 116 the sync slave 224 accepts the clock time 208 unchanged as its own local system time 226 and from this derives its operating clock 228 thus while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof it will be understood that various omissions and substitutions and changes in the form and details of the devices.