Polycom MGC Administrator, Руководство администратора

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Chapter 3 - Defining Network Services
3-100
Defining an MPI Network Service
The MGC unit supports connection to endpoints communicating with
protocols such as V.35, RS-449 and RS-530 over a serial connection. The
MCU can either be Data Terminal Equipment (DTE) or Data Communication
Equipment (DCE).
DCE (Data-Communications Equipment): The equipment that enables a
DTE (the MCU in Figure 3-1) to communicate over a telephone line or data
circuit. The DCE establishes, maintains, and terminates a connection, and
performs the conversions necessary to enable communication over an ISDN
network. It provides the clock to the ports, which are connected to the DCE.
In the configuration described in Figure 3-1, the DCE transmits and receives
data from the MCU using a serial connection and distributes the data to the
appropriate channels of the ISDN connection.
DTE (Data Terminal Equipment): User devices, such as terminals and
computers that connect to data communications equipment (DCE); they either
generate or receive the data carried by the network.
When the MCU acts as a DTE it dials the number of the endpoint. This
number is transferred over a serial connection to the DCE. The DCE
translates this number to the appropriate ISDN switch where it may be routed
to an ISDN endpoint or to another DCE connected serially to an endpoint.
Figure 3-1: Typical Configuration With Serial Connection - MCU as DTE
ISDN Network
MCU
(DTE)
DCE
DCE
Endpoint (ISDN)
Endpoint
Serial
connection
T1/E1
T1/E1
Serial
connection