Mocomtech CDM-570 - Manual (Page 100)

CDM-570/570L Satellite Modem with Optional IP Module Revision 4
Introduction MN/CDM570L.IOM
1–2
1.1.1 EDMAC
To facilitate network management for small networks, the CDM-570/570L incorporates
EDMAC, (Embedded Distant-end Monitor And Control). In this mode, an additional 5%
overhead is combined with the traffic data, (1.6% in Turbo BPSK modes, Turbo Rate 1/2
QPSK/OQPSK, and all data rates greater than 2 Mbps). M&C information is added
(transparent to the user), allowing access to the distant-end modem. In addition,
EDMAC-2 uses 1.6% overhead in all modes for those applications where the 5%
overhead is excessive. The EDMAC and EDMAC-2 modes do not require any additional
cabling at either the local or distant-end Modems. Access to EDMAC is via the standard
M&C control port. Full monitor and control is possible, and the on/off status at the
distant-end carrier can be controlled.
1.1.2 AUPC
An important feature in the CDM-570/570L is the addition of Automatic Uplink Power
Control (AUPC). This feature enables the modem to automatically adjust its output
power to maintain the Eb/No of the remote end of the satellite link constant. This
provides protection against rain fading, a particularly severe problem with Ku-band links.
To accomplish this, the framed (EDMAC) mode of operation must be used, and the
distant end modem constantly sends back information about the demodulator Eb/No
using reserved bytes in the overhead structure. Using the Eb/No, the local modem adjusts
its output power, and a closed-loop feedback system is created over the satellite link.
A benefit of this feature is that whenever EDMAC/AUPC operation is selected, the
remote demodulator’s Eb/No can be viewed from the front panel display of the local
modem. Note that both EDMAC and AUPC can be used simultaneously.
1.1.3 Software – Flash Upgrading
The internal software is both powerful and flexible, permitting storage and retrieval of up
to 10 different modem configurations. The modem uses ‘flash memory’ technology
internally, and new firmware can be uploaded to the unit from an external PC. This
simplifies software upgrading, and updates can be sent via the Internet (from Comtech EF
Data’s Web server), e-mail, or on CD. The upgrade can be performed without opening
the unit, by simply connecting the modem to a 10/100BaseT Ethernet port, or the USB
port of a computer.
USB re-flash not available in this firmware release – please consult factory for release
schedule.
IMPORTANT