Device useful as a master/slave clock for transmitting standard time over a telephone network and a telephone network incorporating the device for transmitting and receiving standard time

A device useful as a master/slave clock for transmitting and receiving time data over a telephone network which comprises a pulse generator (1) capable of being synchronized with a standard master external clock system when said device is operating as a master clock, the output of the generator (1) being connected directly to and also through an I/O interface (3) to a CPU (2) having RAM and EPROM, the CPU (2) being connected to a key board (7) and to a digital display unit (5) through a keyboard/display interface (4), the CPU (2) being connected to an interface (6) capable of making the signals compatible for connecting to a telephone modem, said time data comprising phase information and standard time, the phase of a pulse generated by said pulse generator (1) being set by utilizing said phase information received by said device, said phase information being represented by at least one first character sent at a certain time, second data of said standard time being preceded by at least one second character, minute data of said standard time being preceded by at least one third character, and hour data of said standard time being preceded by at least one fourth character.