United Data Corporation

A Proctor Company


Long Loop Adapters


Telephone Demonstrators

Privacy Modules

Telephone Power Supply



Automatic Ringdown Line

46220 Hot Line
Model 46220 & 46240 Telephone Hot Lines

The Proctor Model 46220 Telephone Hot Line provides a private automatic-ringing telephone line between two telephones without using telco facilities or special equipment and power. When one of the two connected phones goes off-hook, the other phone automatically rings. The unit features user-selectable one-way or two-way ringdown operation and three different ringing patterns. The 46220 is ideal for facilities requiring immediate uninterrupted communications, such as military bases, emergency service centers, entry gates and guard shacks, school campuses, hotel/motel complexes, retail stores, large business offices and private residences. It can also be interfaced with multiline telephone systems to provide a special executive priority line with absolute privacy and independence from other lines.

LineSep.gif (1382 bytes)

How It Works

46220 Schematic

The 46220 is a stand-alone direct line telephone circuit that works independently of the public switched telephone network. The 46220 is completely self contained, providing its own source of 48VDC line power and 20 Hz ringing. The user simply plugs the unit into the nearest standard AC outlet, plugs in the line cords of the two telephones, and lifts the handset of one phone to automatically ring the other. The user can manually select either one-way or two-way ringdown and the desired ringing pattern via switches on the front faceplate. It includes RJ11 modular jacks for quick connection of the telephone line cords. The 46220 can be used with standard, cordless and multiline telephones, or for transmitting data via modems or FAX machines. It is ideal for use as a dedicated telephone-to-telephone hot line, a tie line between two key or PBX systems, or as an Off-Premise Extension (OPX). It c

Typical Applications

46220 Application

LineSep.gif (1382 bytes)

Key Benefits

    Provides automatic ringdown between two
    telephone devices without using telco facilities.
    Completely self contained; includes its own
    power supply and ringing generator.
    User selectable ringing patterns and one-way
    or two-way ringdown.
    Standard 115 VAC operation.
    Modular jacks allow quick connection
    of telephone devices.
    Can be used as a tie line between key or PBX
    systems, or as an Off Premise Extension (OPX).
    UL Listed; meets applicable
    FCC requirements.

Model 46220 Specifications

    • Modular RJ11 Jacks
    • Operating Voltage: 95 to 130 VAC, 60 Hz
      250 mA maximum, 30 watts
    • DC Loop Length: Up to 30,000 feet, 24 AWG wire
      1900 Ohms per loop (each side)
    • Loop Current: 20 mA @ 1.5K Ohms loop
      and Type 500 telephone
    • Loop Voltage: 50 VDC nominal
    • Ringing Generator: 105 VRMS at 20 Hz nominal
      (5.0 REN load)
    • Ringback Tone: 440 and 480 Hz nominal.
    • Ringing Cycle:
      - Standard: 2 seconds on, 4 seconds off
      - Alert: 1 second on, 1 second off
      - Emergency: 4 seconds on, 2 seconds off
    • Operating Temperature:  0 to 50C (32 to 122F)
    • Storage Temperature:  -20 to 85C (-4 to 185F)
    • Humidity: 0% to 95% (Non-Condensing)
    • Dimen: 8.45" (21.46cm) W x 2.5" (6.35cm) H
      x 7.0" (17.78cm) D
    • Wt: 4 lbs, 9 oz (2.06 kg) 


Copyright United Data Corporation, Inc.


Dial-Up Test Set (51200-S)

Dial-Up Test Set (51200F23)

Leased Line Test Set

PBX Test Set

Call Collector


Production Equipment

Lab Equipment

Plastic Housings