Data transmission system and method

A method for transferring digital information which has been converted to a multiframe format of serial bits over a single optical cable, said multiframe format including sequential data frames each containing a sequence of bits having a predetermined bit frequency and including a predetermined number of data bits containing said digital information, the bits being encoded into a single optical signal for transfer by way of the optical cable, and the optical signal then being received and decoded to reproduce the bits, the method of retrieving the digital information from the data bits comprising:

• generating a clock signal having a frequency substantially equal to said bit frequency and having a predetermined phase relationship with respect to the bits, said phase relationship being attained by sensing the duration of each said data frame, determining measured frame intervals using said clock signal, comparing said measured frame intervals and the sensed duration of said data frames, and adjusting the frequency of said clock signal whereby to make said measured frame intervals substantially equal in length to said data frames and to produce said predetermined phase relationship, and using said clock signal to select said data bits from the sequence of bits in each said data frame to retrieve said digital information.

A method of transferring digital information which has been converted to a multiframe format of several bits over a single optical cable, said multiframe format including sequential data frames spaced from one another in time, each containing a trigger bit followed by a predetermined number of data bits containing said data information followed by an end bit said trigger and end bit together providing a unique combination as compared to either of these bits alone or in combination with any other information in the multiframe format the bits being encoded into a single optical signal for transfer by way of the optical cable, and the optical signal then being received and decoded to reproduce the bits, the method of retrieving the digital information from the data bits comprising:

• generating a clock signal having a frequency substantially equal to said bit frequency and having a predetermined phase relationship with respect to the bits, and using said clock signal to select said data bits from the sequence of bits in each of said frames to retrieve digital information, said last mentioned step including the step of processing the data bits for display of said digital information only after both said trigger bit and end bit as evidenced by sensing there unique combination have been transferred over said optical cable.