Common Ringer Matrix

Model 173 Three-Trunk Ringer Matrix

Replaced- see model 173W

Connect multiple CO trunks to a common ringer

Replaced by Model 173W. The Model 173 Common Ringer Matrix, allows connecting multiple Central Office (CO) lines to one common output whenever one of the lines rings. This unit eliminates the necessity of providing a separate bell for each incoming CO line. The Model 173 will accommodate three CO lines. For more than 3 lines you can gang 173s together. The unit also functions as a Ringing Detector.

The 173 unit is easy  to install. Screw terminals allow simple bridge tap connections to the incoming CO lines. No external power is required. The output will drive practically any common audible device (Tip/Ring-powered ringer).

The 173 provides a choice of two outputs, standard ringing voltage or contact closure. Also, the 173 offers special features that allow for multiple unit connections, i.e., expanding beyond three CO lines. Units can be ganged together to accommodate additional CO lines. They also have an auxiliary dry relay contact for operating ancillary equipment. Through the use of a power supply connected through the optional contact closure, a 24 VDC alert signal can be driven.


The perfect solution for organizations that require common audible or night bells. Economize on the cost of installing one bell for each line. The Model 173 allows you to connect all your lines to one bell. Make sure calls are heard when your receptionist goes home. In loud industrial areas, combine with Dees’ Model 196 Loud Industrial Ringer.

Use the dry relay contacts to operate auxiliary equipment. For example, through the use of a power supply connected through the optional contact closure, you can drive a 24 VDC lamp. This application would be suitable for locations that require visible rather than audible notification of a call, such as recording studios, nurses stations, or the hard of hearing.


  • Multiple line grouping (zone signaling)
  • No external power required
  • Auxiliary relay contacts available
  • Units can be ganged together for greater line capacity (example above)



Ring Detection Voltage70 130VAC
REN  1.4B
Contact Rating (Normally open)  2Amps
Caution: Contact protection required when driving inductive loads
Operating Temperature32 122°F
(intended for indoor use only)0 50°C
Humidity  95 %RH

Dimensions (LxWxH)
5″ x 5″ x 1.5″ (12.7 x 12.7 x 3.8 cm)

Shipping Specifications
6.75″ x 6.5″ x 4.5″ (17 x 16.5 x 11.5 cm)
0.80 lbs (0.363 kg)



Approval Number

DOC CS03 350 2941 A
FCC Part 68 FCN8E3-71872-KX-N
2UL1459 D0292442DBC

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