Carrier Access 1750 user manual Unstructured DS3 SAM Configuration Items, Options Comments

Configuration

Unstructured DS3 SAM

Table 7-2: Unstructured DS3 SAM Configuration Items

Item	Options	Comments
Port Name		A descriptive field to identify the port
Port Mode	On-line	This is a status field that can be toggled to online or offline. When the port is in
	Off-line	offline status, it is not available to make calls, and passive SVCs are refused.
Framing	C-bit	C-bitis a framing mode using DS2 stuff bits associated with M23 multiplexing
	M13	for other purposes such as Far End Alarm Control (FEAC) Channel. M13 is a
	Unframed	mode that maps 28 DS1s directly into the DS3. The DS1s do not exist
		independently as is the case when M23 multiplexing is used. Unframed requires
		a 44.736 Mbps input.
Clock Mode	SRTS	NOTE: SRTS is a proprietary timing algorithm and may ONLY be
	Adaptive	used with specific written prior permission from Carrier Access
	Network	Corporation. Additional license fees may apply.
	BITS
	Loop	SRTS-This method measures the Service Clock input frequency against a
		network-wide ATM synchronization clock and sends the difference signals in the
		AAL1 header to the destination Broadmore 1700 circuit emulation interface. The
		different signals are then combined with the network-wide ATM synchronization
		clock to re-create the input service clock. If more than one ATM clock
		synchronization is present in the network, an alternate timing recovery method
		must be selected. For this method to work, the ATM network must be
		synchronized to a single network-wide clock source. User equipment should be
		configured to internal clock.
		Adaptive Timing –This technique maintains a pre-defined fill level in the Circuit
		Emulation Re-assembly buffer to control the timing output to user equipment.
		This method of timing recovery does not require a Synchronous ATM network
		and is used in applications where network wide synchronization is not available.
		(Synchronous) Network-This method of clock recovery derives timing from the
		ATM Network and propagates it to the CE Service Interface. The ATM network
		must be synchronized to a single source clock. User equipment should be
		configured to recover timing from the Broadmore 1700 CE service interface.
		(Synchronous) Loop-The Broadmore 1700 CE interface will derive clock from
		the attached DS3 user equipment and transmit from the CE interface at that rate.
		The user equipment should be configured for Internal timing if the Broadmore
		1700 CE service interface is configured for Synchronous loop.
		BITS- (Building Integrated Timing Supply)- distributes standard timing to
		equipment within the central office. The Broadmore 1700 accepts BITS via either
		NIM IOM. The fallback for the primary BITS clock is the other BITS clock. The
		fallback for no BITS is the internal clock of the NIM.

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