3Com S330 manual OC3/STM-1 Port, To configure the OC3/STM-1 port, follow these steps

104CHAPTER 4: CONFIGURING PATHBUILDER S330/S310 MODULES, PORTS, AND APPLICATIONS

Configuring the	To configure the OC3/STM-1 port, follow these steps:
OC3/STM-1 Port
	The PathBuilder S310 does not support OC3/STM-1; the OC3/STM-1 port is
	disabled on that device.
	1 From the Configuration Management menu, shown in Figure 50, select
	[1] Manage Card to display the List Card menu, shown in Figure 51.
	2 From the List Card menu, select [4] OC3 UNI to open the SONET UNI
	Configuration menu, shown in Figure 74. This menu displays the current
	configuration for the OC3/STM-1 port and provides options that allow you to
	change certain settings.
	Figure 74 Configuring the OC3/STM-1 Port

3Set the following parameters as desired:

Admin. Status—Administrative status: Out of Service or In Service.

Sonet Interface Mode—The SONET interface supports two modes: OC3 and STM-1. Choose the mode used at your location. OC3 is used most often in the United States, while STM-1 is common in other countries.

ATM Payload Scramble—Enables (yes) or disables (no) payload scrambling for the OC3/STM-1 port. The default is disabled (no). Payload scrambling is a technique used to avoid certain transmission equipment behaviors (for example, erroneous alarm conditions) that are caused by sensitivity to certain bit patterns in the ATM payload. When you set payload scrambling to yes, the ATM Payload Scramble scrambles the 48 byte payload in outgoing cells in a defined manner and unscrambles the payload in incoming cells. The payload scramble settings must match at the two ends of the OC3/SDH trunk.

Timing Source—The timing source for the OC3/STM-1 transmit clock.

Loop—Configures the OC3/STM-1 port interface to use the input port Rx clock as the timing source; timing is received from the service “loop.” Select Loop if the OC3/STM-1 port is used for the network/carrier service termination, in which case the carrier (the service “loop”) typically provides the timing source.

System—Configures the OC3/STM-1 port interface to use the internal system clock as the timing source.