The MK2049-02 and MK2049-03 are PhaseLocked Loop (PLL) based clock synthesizers that accept multiple input frequencies. With an 8 kHz clock input as a reference, the MK2049-02/03 generate T1, E1, T3, E3, ISDN, xDSL, and other communications frequencies. This allows for the generation of clocks frequency-locked and phaselocked to an 8 kHz backplane clock, simplifying clock synchronization in communications systems. The MK2049-02/03 can also accept a T1, E1, T3, or E3 input clock and provide the same output for loop timing. All outputs are frequency-locked together and to the input.