How to Troubleshoot FTTH Network?

How to troubleshoot FTTH network?: Many of my friends are working on FTTH network but they are not fully aware of how to properly troubleshoot the FTTH Network.So today I have decided that articles on this topic should be provided.Troubleshooting on an out-of-service network (i.e. on a point-to-point network or when the entire PON network is down) can be conducted simply with the use of a power meter or OTDR.

A live PON network requires the use of a PON power meter to investigate when signals are out of tolerance. To pinpoint any fibre breaks, macro-bending, faulty splices or connectors, an OTDR with a live testing port must be used from the subscriber’s location. Now we will discuss how troubleshooting can be done on PON network.

FTTH Network Troubleshooting by field engineer

How to Troubleshoot FTTH Network

PON network troubleshooting

In PON network troubleshooting the test engineer will connect an OTDR at the output of the drop cable and perform an upstream test using a short pulse width (i.e. 3/5ns). Due to the high loss observed at the splitter location and the relatively low measurement dynamic range provided by a short pulse, the end of the fiber link will be identified at the splitter location.

Ensure the fiber length corresponds to the length in between the drop cable output and the splitter location. If not, this indicates a problem (break or macrobend) is present at this location.

If the length measurement is correct, every splice point should be checked to see it does not exceed the normal splice values. Any point exhibiting an excessive loss value will indicate the presence of a macrobend, kink in the fiber or a bad splice.

The fiber is terminated at the home by an ONU that provides interfaces to serve internet facilities over coaxial cable; video, VoIP, or data over Ethernet; also phone services available over twisted pair wiring. Service providers may wish to provide digital video through quadrature amplitude modulation (QAM) or IPTV or a combination.

Premises architecture incorporating both QAM for broadcast video and IPTV for on-demand, the IPTV video shares the coaxial cable with the QAM digital video and is typically delivered using the Multimedia over Coax Alliance (MoCA) standard. The HPNAv3 protocol can also be used to deliver IPTV and data since it can run on existing twisted pair telephone lines or coaxial cable.

PON troubleshooting

PON network troubleshooting

Troubleshoot In‐home wiring

In addition to loss, latency, and jitter emanating from the fibre network, a number of in-home
issues can combine to degrade the subscriber’s quality of experience, including problems with phone lines, Ethernet wiring mis-configuration or faulty termination, poor coaxial cabling integrity, and noise impairments.

 Issues in FTTH Phone line

Phone lines in the subscriber area often carry both voice service and data services using HomePNA (HPNA) standards. The ONU emulates the POTS network by providing all of the battery voltages, ring tones, and dial tones that were previously provided by the central office. Consequently, troubleshooting VoIP covering phone wiring is very similar to troubleshooting POTS. Below mentioned common errors affecting in-home wiring installations include:

➥opens
➥shorts
➥crossed wires
➥broken wires

Troubleshoot of Ethernet wiring

Today's many homes are pre-wired with twisted-pair wiring suitable for Ethernet data services. Verification of proper termination is very important in troubleshoot FTTH network. Between 75% and 85% of the time in-home technicians dedicate to troubleshooting can be attributed to improper terminations. The most common termination faults can be located using a wiring verifier. Continuity tests include:

➥verification of pin-to-pin connections
➥wire capability to carry a signal
➥shields
➥voltage on line

Locating and resolving coax problems

Existing coaxial home networks present various types of challenges. Built by home builder, owner or perhaps a previous service provider, network quality and route are rarely known. A high-quality coaxial installation should provide at least 30dB noise separation to the outer world (noise immune).However, these networks often contain:

➥splitters
➥pinches
➥breaks
➥bad cables
➥un-terminated ends
➥bad connections
➥amplifiers

Any of these networks can cause problems and problems of service quality. To provide reliable services, it is important to make proper arrangements to repair or replace parts of the network to meet the triple-play service provider standards.

Summary of FTTH optical troubleshoot tools

The following is a list of optical testing tools used for troubleshoot FTTH networks:

Optical tools for FTTH troubleshoot

Tools used for FTTH networks