We Are Just A Phone Call Away

Model 236-104 Signalman's Friend

Portable, battery-powered circuit monitor with alarms, dramatically reduces OS circuit testing time. Seven point shunt test can be completed in two minutes, fifteen seconds. Monitors track circuit voltage and alarms when track voltage drops below 1V. Works with all known types and brands of OS circuits. Can also be activated by dry or powered relay contacts or floating outputs. Magnetic Clamps can connect the “Friend” to the rail. Alarms indicating circuit voltage dropped below 1V are 90dB sounder and 100,000 candlepower strobe light. Alarm format is selectable: one or the other, or both. Settings are retained until changed, even if unit is powered down. Use with S&C Probe or Fast Shunts to further reduce testing time. 

Operating temperature Range:

  •  -22degF to 140degF (-30degC to 60degC). 


  • Universal Charger and HD nylon carry bag. 
  • Kits with Magnetic Clamp Connector Set listed below. 

Tripod for “Friend” also available.

Ordering References: 

  • 236-104-100 Kit with “Friend” Charger & HD Carry Bag 
  • 236-104-105 Above, but also with Magnetic Clamp Connector Set
  • 236-104-110 Above, but also with Tripod for “Friend”