Chapter 11. Troubleshooting

2.Disconnect the ISU 128 from the ISDN line. From a functioning voice phone, call the local directory number(s) provided with your line. Calling a good ISDN line with nothing connected usually results in a ring or fast busy tone. If someone answers or a not-in-service intercept is received, there is probably something wrong with the translation of the ISDN line. The phone service provider should be able to help.

3.If the ISU 128 continues to read Link Down, there is a physical problem with the ISDN phone line (more than likely, a problem with the Layer 1 setup). The problem may be one or more of the following:

•The ISU 128 software setup

•The ISU 128 hardware

•The wiring on your premises

•The telephone service provider's wiring

•The telephone service provider's hardware

•The telephone service provider's software setup

To isolate the problem, perform the following procedure:

A.Make sure the ISU 128 is configured for dial line service. Check that

CONFIG, Netw. options, Dial Line, is selected on the menu.

B.Try another piece of functioning ISDN equipment with a U-interface on the ISDN line.

C.Talk to your service provider and ensure you have an ISDN Basic Rate U-Interface with 2B1Q line coding (wrong options are an S or T interface or AMI line coding).

D.Ensure that your ISDN phone line is connected to the actual telephone line (U-interface) provided by your telephone company. Make sure your ISDN line is not connected though another piece of equipment such as an NT1 in a wiring closet somewhere.

E.Make sure nothing else is bridged across the ISDN line pair.

F.With a minimum of extra wiring, try connecting to the ISDN line pair at the point where service provider's wiring ends.

78

ISU 128 User Manual

61202.029L2-1

Page 92 Page 94
Page 93
Image 93
ADTRAN ISU 128 user manual CONFIG, Netw. options, Dial Line, is selected on the menu
Page 92 Page 94

ISU 128 specifications

The ADTRAN ISU 128 is a versatile and robust integrated service unit designed for network access solutions, particularly within telecommunications and enterprise environments. This unit plays a critical role in enabling high-speed data transmission, supporting various voice, video, and data services over traditional and next-generation networks.

One of the noteworthy features of the ADTRAN ISU 128 is its ability to aggregate multiple digital circuits into a single access point. It supports T1, E1, and fractional T1/E1 interfaces, making it a flexible choice for customers with different bandwidth needs. The unit allows for seamless migration from legacy systems to modern broadband services, ensuring that businesses can scale their operations without significant infrastructure changes.

The ADTRAN ISU 128 also excels in its support for various protocols, including Frame Relay and ATM, providing the necessary flexibility to adapt to different network architectures. This adaptability is essential for businesses that rely on diverse communication platforms to maintain connectivity and operational efficiency.

Another significant aspect of the ISU 128 is its built-in features for diagnostics and monitoring. The unit includes comprehensive loopback and performance monitoring capabilities, which enable network administrators to troubleshoot potential issues proactively. This functionality ensures a reliable connection and minimizes downtime, which is critical for maintaining service-level agreements (SLAs).

In terms of user interface, the ADTRAN ISU 128 is designed with ease of use in mind. The unit can be configured and managed through a web-based graphical user interface, allowing for straightforward remote access to settings and performance metrics. This capability facilitates quick adjustments and upgrades, helping to streamline network management tasks.

The ISU 128 is also built with a strong emphasis on reliability and durability. It is housed in a compact, rack-mountable design, making it suitable for various deployment environments. These characteristics, combined with support for redundant power supplies, enhance the unit's reliability in critical operations.

Overall, the ADTRAN ISU 128 stands out as a powerful solution for organizations seeking to optimize their network access. With its advanced features, compatibility with multiple technologies, and emphasis on reliability, the ISU 128 is an ideal choice for those looking to enhance their communication infrastructure in a rapidly evolving digital landscape.
Top Page Image Contents