GLS-12 - Viking Electronics

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Use Loop Start Devices on Ground Start Trunks

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Product Details

Model GLS-12 is designed to allow up to 12 standard telephone sets, multi-line key systems or other loop start equipment to be connected to and operate on two-wire ground start CO trunk lines. The GLS-12 provides the CO ground start line with the signalling required to draw dial tone when the loop start equipment goes off-hook. Incoming calls are not affected by the GLS-12 and ring directly to the loop start devices.


  • Allows PABX and key systems configured for loop start trunks, as well as standard telephones to be connected to C.O. ground start trunks
  • Eliminates wiring ground start buttons in standard telephones



  • 12 circuit automatic ground start to loop start equipment converter
  • Stackable to increase capacity
  • Easy, straight forward installation via an RJ-21X 25 pair connector


  • Power: The unit is powered by the 48V ground start CO trunk lines – no AC power supply required
  • Dimensions: 5.25” x 3.5” x 1.75” (133mm x 89mm x 44mm)
  • Shipping Weight: 2.5 lbs (1.13 kg)
  • Environmental: 32°F to 90°F (0°C to 32°C) with 5% to 95% non-condensing humidity
  • Connections: (1) RJ-21X female, 25 pair