Comtech EF Data CDM-840 - Manual (Page 179)

CDM-840 Remote Router Revision 2
Appendix A MN-CDM840
A–5
A.5 Entry Channel Mode (ECM)
ECM operation is available in the CDM-840 and ODM/R-840 Remote Routers, and the CDD-880
Multi Receiver Router. ECM is a feature based on slotted Aloha with random retransmission
backoff. It supports multiple carriers through frequency assignments, which provide simplified
deployment and scalability.
While a CDM-840 or ODM/R-840 is in Entry Channel Mode, it allows the passing of management
traffic only – it will not transmit user data traffic. An ECM-enabled 840 may remain in the entry
channel for an extended period if “online” communications are not required, or if dSCPC
(dynamic Single Carrier Per Channel) resources are unavailable. While idle or waiting in the entry
channel, the 840 sends periodic health status messages to the CTOG-250 and Vipersat
Management System (VMS) while it continues to service VMS recovery logic timers.
• Appendix F. ENTRY CHANNEL MODE (ECM) in this manual
• Appendix F. ENTRY CHANNEL MODE (ECM) in the Comtech EF Data ODM-840
Outdoor Remote Router / ODMR-840 Reduced Form Factor Outdoor Remote
Router Installation and Operation Manual (CEFD P/N MN-ODM840)
• Appendix D. ENTRY CHANNEL MODE (ECM) in the Comtech EF Data CDD-880 Multi
Receiver Router Installation and Operation Manual (CEFD P/N MN-CDD880)