ADC ETU-751C, UTU-701C Unstructured Mode

Functional Description 700-701-100-02

Unstructured Mode

When 32 time slots are selected, the line and desktop units automatically operate in the unstructured mode (see “G.704 Framing and Rate Selectable HDSL” on page 17). There is no unstructured menu selection.

In the unstructured mode:

•There is no G.704 framing.

•Time slot 0 is the beginning time slot, and the data rate is fixed at 2048 kbps.

•A transparent transmission channel is provided between the local and remote units.

•CRC-4 detection and generation are not available, and E1 alarms are limited.

Any framing, multiframing, and common-channel signals can be transmitted through the HDSL line units in the unstructured mode, but the units do not monitor for a loss of framing condition.

Table 8 lists system settings for 2048 kbps transport of data between a DTE connected to an UTU-701C and a DTE connected to an ETU-751C. The settings in Table 8 use the G.703 signal from the UTU-side DTE as the primary timing source. Timing at the ETU side is recovered from the received G.703 signal. This application is illustrated in Figure 7.

Table 8. Typical Unstructured Mode System Settings

		Options				Setting
		Application Mode				32 TS (Unstructured)
					UTU-701C (LTU) Interface
		Primary Timing Source				G.703
		G. 703 Port
			CRC Mode			N/A
			Idle Code			FF
			Data Rate/# of TSs			2048 / 32 TSs
			Beginning TS			0
					ETU-751C (NTU) Interface
		Primary Timing Source				G.703
		Data Rate / # of TSs				2048 / 32 TSs
		Beginning TS				0
	Network Side								Customer Side
			UTU-701			Single Pair	ETU-751
			(LTU)				(NTU)
						HDSL loop
				HDSL			HDSL
	32					32				32
Exchange
	Time Slots									Time Slots	Customer
Office			G.703			Time Slots		G.703
	(2048 kbps)									(2048 kbps)	DTE
DTE						(2048 kbps)

Figure 7. Unstructured Mode Application

16 August 9, 2002 UTU-701 and ETU-751 List 1