The MTT ACM II Chassis features a family of plug-in modules, providing stringent and comprehensive testing to qualify the copper pair in physical layer

The MTT ACM II (Modular Test Toolkit Advanced Cable Maintenance) provides the industry’s premier handheld test set for qualifying the copper pair for different DSL services including VDSL2, ADSL2+ and SHDSL services. The ACM II covers an industry best frequency range from voiceband to 30 MHz – necessary for FTTN and MDU applications based on VDSL2. In addition, the flexible configuration of this host chassis can support DSL, optical, and other MTT modules making it the only high-speed solution offering complete FTTN/x testing in one package.

Integrated into the test set are key cable maintenance features including a resistance fault locator (RFL), spectrum analysis, dual trace time domain reflectometer (TDR) and digital multimeter enhancing troubleshooting and repair. Using the MTT ACM II enables service providers to complete installations in less time and with greater confidence in the quality of service delivered to customers.

Highlights

• Physical layer testing for different DSL flavors including VDSL2, ADSL2+ and SHDSL
• Dual Trace TDR for in-depth fault location
• RFL to locate resistance faults
• Patented Detaptor function to identify bridge taps and determine its length
• Impulse noise
• DMM
• Load coil detector
• NEXT/FEXT
• Supports many SSMTT/SSxDSL test modules

Dual Trace Split Screen

Resistance Fault Locator Screen

 

Copper testing for VDSL

Spectrum management with PSD background

Spectrum management is a key challenge for service providers deploying high speed services. Since VDSL2 uses up to a 30MHz spectrum, it is particularly susceptible to interference from outside sources (both the European and US standards allow amateur radio bands within the VDSL2 spectrum). Interference can be harmful to VDSL2 systems' data rate and signal to noise margin.

The extended range of the SunSet MTT ACM II PSD (Power Spectral Density) Background Noise measurement enables the service provider to properly assess spectral compatibility issues for multiple VDSL2, ADSL2+, SHDSL, and other high frequency signals residing in the same binder group. This test is an essential tool for troubleshooting marginal circuits.

Insertion loss testing for the full frequency range

Insertion Loss is a tried and true testing technique used for gauging transmission quality. The loss for a particular frequency increases with distance and in general, the higher the frequency, the greater the attenuation. Traditionally, insertion loss has been used to pre-qualify lines for POTS transmission and ADSL. The technique is easily applicable for ADSL2+ and VDSL2.

In addition, VDSL2 utilizes a frequency spectrum well above other DSL and legacy services. Consequently, unlike legacy transmission schemes, VDSL2 is susceptible to the notch effect caused by short bridge taps. In the example loop shown, a bridge tap only 15 ft (5 m)in length represents a transmission impairment centered at about 9.5 MHz,impacting a frequency range from 7 MHz to 12 MHz, well within the VDSL2 spectrum.

To complicate the matter, depending on the test access point, short bridge taps are not always detectable with a TDR. The most effective method of short bridge tap detection is to use the patented Detaptor feature of the SunSet MTT ACM II. The Detaptor uses the frequency sweep insertion loss measurement to detect bridge taps. The Detaptor is useful for cases where the bridge tap’s length and positioning render it undetectable with a TDR.

The extended frequency range supported by the SunSet MTT ACM II is essential to address the full 30 MHz VDSL2 band plans in use today.

TDR

The SunSet MTT ACM II’s TDR can locate bridge taps, load coils, opens, and shorts when pre-qualifying the copper plant for VDSL2. In addition to the outside plant copper pair fault detection, its TDR has been optimized for enhanced performance over the short cable distances used inside a home in FTTN deployment.