Comtec CDM-840 Installation And Operation Manual page 34

CDM-840 Remote Router
Introduction
The CDM-840 features one 10/100/1000 Gigabit Ethernet (GigE) interface, one 10/100 Fast
Ethernet (FE) interface, and provides WAN bandwidth optimization. It also features integrated
VersaFEC, a patented system of short-block codes that provide maximum coding gain with
lowest possible latency.
1.2 Functional Description
The CDM-840 Remote Router:
•
Transmits VersaFEC interoperable with Comtech EF Data's CDD-880 Multi-Receiver Router.
The receive side supports DVB-S2 operation at L-Band up to 62 Msps, and is compatible with
Comtech EF Data's CTOG-250 Comtech Traffic Optimization Gateway/CDM-800 Gateway
Router for ACM/VCM (Adaptive Coding and Modulation / Variable Coding and Modulation)
operation.
•
Features a high performance processor and a real-time operating system (RTOS) combined
with multiple Field Programmable Gate Arrays (FPGAs).
•
Runs on an embedded operating system in non-volatile Flash memory. It does not have
moving parts for media storage.
•
Supports reception and transmission of IP data over satellite links via two fundamentally
different types of interface – IF and data:
o The IF interface provides a bidirectional link with the satellite via the uplink and downlink
equipment.
o The data interface is a bidirectional path that connects the customer's equipment
(assumed to be the Data Terminal Equipment, or DTE) to the unit (assumed to be the Data
Communications Equipment, or DCE). All terrestrial data is connected using the available
10/100/1000 Gigabit Ethernet interface.
•
Includes support for ACM (Adaptive Coding and Modulation) and CCM (Constant Coding and
Modulation) operation:
o ACM allows the modulator to automatically and seamlessly adjust the transmitted
MODCOD as the environmentally conditions change to maintain QEF (Quasi Error Free)
operation.
o VCM allows operators to define groups of remotes on the outbound having different
modulation and coding parameters, as a means to improve efficiency on existing satellite
capacity.
On the Tx (transmit) side: The return modulator transmits IP datagrams and is compatible with
Comtech EF Data's CDD-880 Multi-Receiver Router(s) located at a hub site.
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