H4TU-R Network Loopbacks, Customer Loopbacks

H4TU-R Network Loopbacks

The loopback position is a logic loopback located within the H4TU-R internal HDSL4 transceiver. See Figure 4.

			H4TU-C Network-Side Loopback
					AIS
		DSX-1		LOCAL	DS1
		DSX-1		LOOP	DS1
				LOOP	X
					X
			H4TU-C		H4TU-R
			H4TU-R Network-Side Loopback and/or
			H4TU-R NIU Loopback
					AIS
		DSX-1		LOCAL	DS1
		DSX-1		LOOP	DS1
				LOOP	X
					X
			H4TU-C		H4TU-R
			H4TU-R Customer-Side Loopback
			X
		DSX-1		LOCAL	DS1
		DSX-1		LOOP	DS1
				LOOP
		AIS	H4TU-C		H4TU-R
			H4TU-C		H4TU-R
			H4TU-C Customer-Side Loopback
			X
		DSX-1		LOCAL	DS1
		DSX-1		LOOP	DS1
				LOOP
		AIS	H4TU-C		H4TU-R
		H4R Network-Side Loopback
						AIS
	DSX-1					DS1
					X
		H4TU-C		H4R	H4TU-R
		H4R Customer-Side Loopback
		X
	DSX-1					DS1
						DS1
	AIS	H4TU-C		H4R	H4TU-R
	H4R1 Network-Side Loopback					AIS
						AIS
DSX-1						DS1
						X
	H4TU-C			H4R1	H4R2	H4TU-R
	H4R1 Customer-Side Loopback
	X
DSX-1						DS1
AIS	H4TU-C			H4R1	H4R2	H4TU-R
	H4R2 Network-Side Loopback					AIS
						AIS
DSX-1						DS1
						X
	H4TU-C			H4R1	H4R2	H4TU-R
	H4R2 Customer-Side Loopback
	X
DSX-1						DS1
AIS	H4TU-C			H4R1	H4R2	H4TU-R
				X = Signal Inactive

Figure 4. HDSL4 Loopbacks

The H4TU-R responds to multiple loopback activation processes:

•First, manual loopback on the H4TU-R and/or the H4TU-C unit may be controlled from the front panel. Refer to the Front Panel Operation section of this practice for more detail.

•Second, loopback activation may be accomplished using the control port of the H4TU-R.

•Third, the H4TU-R will respond to the industry standard HDSL loopback codes as designated in the ANSI document T1E1.4/92. These are described in Appendix A, HDSL4 Loopbacks.

•Fourth, the H4TU-R responds to T1 Network Inter- face Unit (NIU) loopback codes as described in Bellcore TR-TSY-000312, as follows:

In-Band Codes
Loop up	11000 (2 in 5)
Loop down	11100 (3 in 5)
ESF Codes
Loop up	1111 1111 0100 1000 (FF 48)
Loop down	1111 1111 0010 0100 (FF 24)

Receiving the in-band codes for more than five seconds or the ESF codes four consecutive times will cause the appropriate loopback action. The ESF codes must be transmitted in the Facility Data Link (FDL).

NOTE

The NIU loopback option must be enabled before the H4TU-R can respond to the NIU loopback.

The H4TU-R will respond to the loopback codes by activating the NIU loopback from either the disarmed or armed state. The loop down codes will return the H4TU-R to the disarmed or de-activated state depending upon the code utilized.

Customer Loopbacks

In addition to the loopbacks in the direction of the network, the H4TU-R may also be looped back in the direction of the customer. The H4TU-C and H4TU-R Customer Side Loopbacks are illustrated in Figure 4.

NOTE

Network and customer loopbacks are governed by the loopback time out option (Default=120 minutes).

Issue 1, December 2003

61223424L2-5A

T200 H4TU-R specifications

The ADTRAN T200 H4TU-R is a versatile and advanced telecommunications device designed for high-speed data transmission and enhanced connectivity. It serves primarily in carrier-grade applications, enabling service providers to deliver reliable broadband services to their customers. This device integrates multiple features and technologies that ensure optimal performance and flexibility in various networking environments.

One of the key features of the T200 H4TU-R is its ability to support high-speed data services over existing copper or fiber infrastructures. It utilizes G.SHDSL technology, which allows for symmetrical data rates ranging from 192 kbps to 5.7 Mbps, making it suitable for both enterprise and residential applications. This capability is essential for businesses requiring dedicated bandwidth for applications like VoIP, video conferencing, and cloud services.

The T200 H4TU-R also supports various interface options, including Ethernet over G.SHDSL and T1/E1 lines, which provides compatibility with multiple legacy systems. This flexibility extends the useful life of existing networks while enabling a smoother transition to newer technologies. The device features dual Gigabit Ethernet ports, allowing for easy integration into modern networking setups while facilitating network redundancy and load balancing.

Built with scalability in mind, the T200 H4TU-R can accommodate the growing demands of service providers. Its management capabilities are further enhanced by support for SNMP and Web-based interfaces, enabling operators to monitor network performance and promptly address any issues that arise.

Another significant characteristic of the T200 H4TU-R is its robust error correction capabilities, which ensure data integrity and minimize the risk of data loss during transmission. It employs advanced technologies such as H4 (High Capacity) coding and interleaved mode, effectively increasing data rates while maintaining reliability.

For installations, the device offers versatile powering options, including Power over Ethernet (PoE), which simplifies deployment while reducing cabling requirements. Additionally, its compact form factor enhances space efficiency in network closets.

In summary, the ADTRAN T200 H4TU-R delivers a powerful combination of speed, reliability, and flexibility. Its advanced G.SHDSL technology, support for various interface types, robust error correction, and management capabilities make it an ideal choice for service providers looking to enhance their broadband offerings while ensuring future scalability and performance.