The RSR CSAC Module is the smallest and lowest-cost CSAC module JLT makes. The commercial version is designed to be plugged directly into a customers’ PCB, or to be connected using a cable harness. The module is disciplined by an optional external 1PPS source, or optional external GNSS receiver. A SAASM version is also form-fit-function compatible to the Rockwell RSR SAASM puck receiver, and can be mounted below the RSR puck adding CSAC GPSDO holdover capability to the popular Rockwell RSR puck. The module works from 2.5V to 5.5V and has extremely low power consumption of typically less than 0.38W. The module contains a dual-input 20 picosecond resolution time-stamping circuit for disciplining from two independent and optional external 1PPS sources, USB connectivity, as well as RS-232 connectivity to external GNSS receivers. The module is shielded for additional protection from EMI.