The Mayhem tone caller emits a loud piercing tone and must be fitted where it cannot cause acoustic shock. Cabling should be disconnected at distant end before approaching a Mayhem tone caller on installation or maintenance visits.

As the Mayhem Tonecaller is used as a replacement for the BT Hooter 2C, it should be noted that the Mayhem is LINE POWERED and the Hooter 2C is MAINS POWERED. As this obviously has serious safety implications, every engineer must ensure that all safety precautions are taken when visiting a site where a Mayhem or Hooter 2c is installed, repaired or replaced.

The Tone caller No. 15 (other companies market it as a Mayhem) - High output weather resistant hard wired (via IDC and screw terminals), high impedance tone caller (derived from BT Tone Caller No. 13A). Supersedes BT Hooter 2C for new supply and maintenance replacement, incorporates (internal) volume control, available on rental terms only.

Made by Hosiden Besson Ltd.

Mayhem tone caller - Approval Number S/1000/3/M/502099

Mayhem tone caller - for interior and exterior use, up to 105 dBA output, requires cabling to PST system. Measures approx. 120mm x 92mm x 114mm (including cable entry gland), weight 420 grams. Requires 4 No. 10 round-head, rust-resistant screws. Cable entry gland may be removed to provide 20mm conduit entry.

REN 1.5.

Phone sockets provided for plug-ended ringing devices should have all conductors terminated in accordance with standard cabling practice so that they may be used for connection of other apparatus if required. Where for engineering reasons (e.g. PBX Night Bell) or at customer request the ringer must not be unplugged, the plug may be secured at the socket by fitting a locking bar.

When wall mounted, the cable entry should face downwards. The Mayhem should be mounted facing the direction that sound is to be projected and may be mounted facing downwards from an overhang or ceiling but must never be mounted facing upwards where dust or water may collect through the sound aperture.

The volume control of Mayhem is normally supplied set to maximum (clockwise) and may be adjusted on installation if customer or situation require otherwise. If Mayhem is left set to maximum volume it must not be mounted within 3 Metres of persons using the area.  Access to the volume adjuster is via the four body fixing screws.  The adjuster is in the base of the warbler unit.

The Mayhem tone caller is line powered and when used to maintenance replace a mains powered Hooter 2C, the associated mains relay Switch Unit 1A must be disconnected (if connected by mains plug and socket) and recovered. The telephone system may also need to be converted to PST.

Where the addition of bells tone or callers results in ringing difficulties because the system is approaching or exceeding REN limitations or capacity of PBX Night bell port, it may be necessary to fit a 'Convertor Ringing 15' to boost ringing output.

Also marketed as the Bedlam Loud Tonecaller by Hosiden Beeson.

Connection to PST jack.

Base Unit Terminal Line Jack IDC connector
2 3
3 5


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Last revised: October 30, 2022