3Com MSR 50, MSR 30 manual Timer dl, Release-guard, View R2 CAS view, 2671

2671

Use undo tdm-clockcommand to restore the default.

By default, the TDM clock source for an E1 or T1 interface is the internal clock.

When digital voice E1/T1 interfaces perform TDM timeslot interchange, it is important for them to achieve clock synchronization to prevent frame slips and bit errors.

Depending on your configurations on E1/T1 interfaces, the system adopts different clocking approaches. When there is a subcard VCPM on the mainboard, the clock distribution principle is as follows:

■If the line keyword is specified for all interfaces, the clock on the interface with the lowest number is adopted. In case the interface goes down, the clock on the interface with the next lowest number is adopted.

■If the line primary keywords are specified for one interface, the clock on the interface is adopted. In one system, you can do this on only one interface.

■If the line keyword is specified for one interface and the internal keyword for all others, the clock on the interface is adopted.

■Normally, you cannot set the clock source for all interfaces in a system to internal. This is to prevent frame slips and bit errors. You can do this however if the remote E1/T1 interfaces adopt the line clock source.

When there is no VCPM on the mainboard, the configuration of each MIM/FIC is independent but only one interface is allowed to be set to line primary on the same device.

Example # Set the TDM clock source on interface E1 1/0 to line clock.

<Sysname> system-view

[Sysname] controller e1 1/0

[Sysname-e1 1/0] tdm-clock line

timer dl

Syntax	timer dl { answer clear-back clear-forward seizure re-answer release-guard }
	time
	undo timer dl { answer clear-back clear-forward seizure re-answer
	release-guard }
View	R2 CAS view
Parameter	answer time: Timeout time in milliseconds of R2 answer signal, in the range of
	100 to 120,000 with a default of 60,000. After the originating point sends a
	seizure acknowledgement signal, the terminating point should send back an
	answer signal within the timeout time. If the terminating point fails to send an
	answer signal within the timeout time, the originating point will clear the
	connection. Timeout time of R2 answer signal should be configured at both the
	originating point and the terminating point. The timeout time of answer signals
	from the terminating point is configured at the originating point, while the