The 260B consists of a motherboard that connects up to four daughterboards to the IP 1553 serial bus. Each of the modules has 16 pressure or temperature channels, a frequency counter, 12 TTL digital input channels, eight TTL output channels, and four open-drain outputs
with 2 A current capability. Each module has both nonvolatile memory
to store zero and gain coefficients as required to calibrate the channels and an on-board Digital-to-Analog (D/A) converter to generate accurate DC voltages for calibration. The modules include an RS232 bus for updating the flash to install new firmware changes. The serial data from the four modules is time division multiplexed, assembled, and
delivered to the bus with a 60 updates/s rate.