Medicare Claims Processing Manual (Pub. 100-04), Ch. 24 § 50.1.1
System Availability
50.1.1 - System Availability
(Rev. 2803, Issued: 10-28-13, Effective: 09-17-13, Implementation: 09-17-13)
Access to A/B MACs, DME MACs and CEDI to exchange electronic transactions and/or
lookup files (e.g., HCPCS codes, fee schedules) may be dependent upon hours the core
processing system is available. Where EDI functions are dependent upon the operation
of the host processing system, the host system’s hours of operation determine system
availability. A/B MACs, DME MACs and CEDI shall inform users of system
availability schedules including any planned downtime for system maintenance.