LHCb vertex detector electronics timing and synchronization

Synchronization of the electronics is the key issue at LHC with the short-bunch crossing period, the very high trigger rate and the large number of detector channels. The vertex detector signals from 200 K channels have to be sampled optimally. The consistency of the event data fragments from all detector channels must be guaranteed during data flow in the front-end and off-detector electronics and the data acquisition system. The ongoing activity in the LHCb vertex detector is described. The necessary synchronization hardware and procedure to detect synchronization errors and to recover with a minimum data losses are presented.