CHARM I/O Scanner Modules install in CHARM I/O Gateways and Blocks. CHARM I/O Scanner Modules installed in CHARM I/O Gateways communicate with the CIOC or CSLS. CHARM I/O Scanner Modules installed in CHARM I/O Blocks communicate with the CHARM I/O Scanner Modules in the CHARM I/O Gateway.
Simplex operation requires one CHARM I/O Scanner Module in each gateway and block. Redundant operation requires two CHARM I/O Scanner Modules in each gateway and block.