3com S330 ユーザーズマニュアル

C

HAPTER

 4: C

ONFIGURING

 P

ATH

B

UILDER

 S330/S310 M

ODULES

, P

ORTS

, 

AND

 A

PPLICATIONS

FEAC Loopback (DS3 only)—Enables or disables the system from responding 
to FEAC (Far-End Alarm Condition) loopback commands (loopback activate and 
deactivate FEAC codes) from the central office. FEAC is a DS3 overhead 
function that the service provider may use for establishing loopback for 
problem resolution of the network. The service provider uses FEAC codes to 
obtain downstream or upstream conditions of a DS3 network. When the FEAC 
Loopback option is enabled, the system responds to a loopback activate 
command by enabling the DS3 line loopback. The system removes the 
loopback automatically after 15 minutes or when it receives the deactivate 
command.

DS3 Timing Source (DS3 only)—The timing source for the DS3 transmit clock: 
system or loop. If you set the DS3 Timing Source to system at one end of the 
DS3 trunk, you must set it to loop at the other end.

System—Configures the port interface to use the system reference clock 
within the shelf as a reference for transmitting.

Loop—Configures the port interface to use the input port Rx clock as the 
timing source; timing is received from the service “loop.” Select this option 
if the DS3 UNI module is used for the network/carrier service termination, in 
which case the carrier (the service “loop”) typically provides the timing 
source.

E3 Timing Source (E3 only)—The timing source for the E3 transmit clock: 
system or loop. If you set the E3 Timing Source to system at one end of the E3 
trunk, you must set it to loop at the other end.

System—Configures the port interface to use the system reference clock 
within the shelf as a reference for transmitting.

Loop—Configures the port interface to use the input port Rx clock as the 
timing source; timing is received from the service “loop.” Select this option 
if the E3 UNI module is used for the network/carrier service termination, in 
which case the carrier (the service “loop”) typically provides the timing 
source.

PLCP Timing Source (DS3 only)—The PLCP timing source for the DS3 port:

System Clock—PLCP is timed from the internal 8kHz backplane clock.

DS3 Timing—PLCP is timed from the 8kHz reference clock derived from 
the received PLCP.

CTX Timing Source—The CTX timing source for the DS3/E3 port.

DS3/E3 Rx Clock—Selects the DS3 or E3 Rx clock as the CTX timing source.

Configuring the serial interface involves the following tasks:

n

Configuring the serial port

n

Configuring the serial card