I-Stop Filter

Reverse Test Probe

The I-Stop reverse test probe is a test accessory you can use with signal level meters and/or analyzers for bi-directional measurements with no risk of power damage.

Introducing the I-Stop™ Reverse Test Probe

The I-Stop reverse test probe is a test accessory designed for use with:

  • Most signal level meters
  • VIAVI DSP™ meters
  • VIAVI ONX meters
  • VIAVI 860 DSPi™
  • VIAVI PathTrak/XPERTrak
  • ViewPoint/SST


Simply screw the probe into a KS port on the distribution tap, connect the field meter to the test port, then press the button on the side of the probe. If the headend ingress displayed decreases by 4 to 6 dB when the button is pressed, the source of the ingress is farther from the node than the test point. Ingress that does not decrease is entering the system nearer to the node than the test point. The I-Stop probe has little or no visible effect on forward path signals.

The I-Stop reverse test probe is the fastest and safest way to track down reverse ingress with any device that can see the headend ingress view, all the while saving time and operational expenses. Screw the probe into the unused KS port of a distribution tap and a spring-loaded “stinger” will connect a nominal 20 dB resistive test point circuit to the seizure screw. The connection is bi-directional, so that an SLM or analyzer connected to the probe can measure forward and reverse signals, as well as reverse ingress. Also, a built-in AC/DC blocking circuit protects the SLM or analyzer from damage from online power up to 100 volts.


Track Down Ingress Fast
The I-Stop probe also contains a patented circuit that is used with the VIAVI PathTrak/XPERTrak or Guardian II System™ return path maintenance system to track reverse ingress sources down to the nearest tap. Using the I-Stop probe, the return path monitoring system and this simple test, all ingress sources can be located all the way down to the tap without removing reverse pads or diplexers and without disrupting forward or reverse service.


Key Features

  • Taps unused KS ports for bi-directional measurements
  • Compatible with SLMs, reverse and forward path analyzers
  • Enables tracking reverse ingress to the nearest tap
  • Protects instruments from linepower damage (up to 100 volts)