The PM 6673...76 series of universal frequency counters offers automatic time and frequency measurements under micro- computer control. For application in measuring systems, provision is made by an interface option for full IEC-625 /IEEE-488 bus program- mability. Other data interface options, like BCD and analog output, are also available. An internal rechargeable battery unit is available to enable the counter to be used in field applications. The Frequency counter PM 6677 is equal to the PM 6676 except for its improved ability to measure high frequencies.