Polycom DOC2238A - Manual (Page 89)

MGC+ Hardware and Installation Manual
4-9
The Main Control Module includes several connectors. These are connected
to ports on the chassis. Two types of connectors on the rear panel provide
connections from the MGC+ to various external systems. These systems
include reservation systems, local or remote operator consoles, management
systems and billing systems. One connector is a standard Ethernet LAN
interface, which support operator workstations operating on LANs via TCP/
IP. The other connector is an RS-232 interface on COM2, which is used for
local diagnostics and production purposes.
An RS-232 interface connector on COM2 the rear panel is provided for
connecting to operator workstations locally or remotely (via a modem). The
connector is used for local diagnostics and production purposes.
The Main Control Module Control Bus connects to the Functional Modules.
The CCOM and C8M provides the interface between the Main Control
Module and the Backplane. This module also generates the MCU clock. The
operating system running on the Main Control Module uses the Processor’s
internal clock interrupts to set up its real-time clock. Sometimes, the
operating system’s clock may skip one or several interrupts resulting in a time
difference between the two clocks. In such a case, the operating system
compares the two clocks. When a discrepancy between the two clocks is
detected, the operating system updates its clock according to the Main
Control processor’s clock. This feature ensures that long-term reservations
start on time.
This feature does not correct any time difference between the MGC+ Manager’s
clock (which is derived from the Windows operating system run on the operator
workstation) and the MCU internal clock.