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Telephone Cut Off Timer Kit (1 - 20 Min.) image Zoom

Telephone Cut Off Timer Kit (1 - 20 Min.)

SKU: FK322
Cuts off the phone after a set time between 1 and 20 minutes.

Availability: Out of stock



Assembly Required!
Product Description


    With this kit you never have to let your teenager tie up the valuable phone line again.
    Cuts off the phone after a set time between 1 and 20 minutes. Gives you a two second warning.
    You have twenty seconds to comply, and if you don't, then it disconnects the phone line for about ten seconds.

    Gets its power from the phone line itself.

    Can fit inside FB17.

    PCB dimensions : 3.7 X 2.2

    A bit more information,

    FK322 telephone cut off timer.

    Based on the CMOS 4060 ripple counter.

    Uses an RC oscillator in combination with on chip oscillator to achieve a base clock rate of between 6 and 100 HZ, Using CMOS logic permits low power consumption and low voltage operation. A power supply voltage of 3.6 volts obtained from the phone line, regulation is provided by a 3V6 zener diode. Using a 4093 Quad gate allows the tone and tone warning period as well as cutoff timer to be built using simple RC parts. When the timer expires a warning tone is produced for about 2 seconds, then after a few second delay the phone line is disconnected and routed through an on board termination resistor. Until the phone on the FK322 is returned back on hook (for a certain duration), the phone current will be rerouted, basically ending the call. You could change the timing by altering the value of C7 C8 .1 and .027, which form the main time period oscillator.

    Longer tone warning by increasing C5 a 10 uF capacitor.

    Current draw is around 5mA.

    Solder posts are provided for your connections, we recommend using 2 off the shelf phone jacks (female, the type usually found on baseboards), wire one to the incoming and one to the outgoing, this way you can just unplug and move or change in an instant.

Additional Information

    Additional Information

    SKU FK322
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