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Surge Protection for Telephone Modems

The proliferation of modems in electronic equipment is widespread today and
makes them susceptible to damage by surges.  The cause of this damage is the
potential voltage difference between the ground at the modem and the ground
at the telephone exchange.

When protecting telephone modems from surges, it is important to note that
the Telephone Company provides a gas discharge tube at its demarcation point
to protect the user from being shocked.  Since a gas discharge tube does not
fire until the voltage exceeds 700 Volts, the potential voltage difference
is already 700 Volts.  Added to that amount is the increase of voltage
difference that results from a ground wire length of at least 3 feet, and
thus the potential voltage difference before the discharge tube fires and
the device being protected is closer to 1200 Volts -- enough power to
destroy the device.

MTL's solution is the ZB24501 surge suppressor, a DIN rail mount model with
RJ45 connections.  It is UL listed, is only available in connector fashion,
and is easy to install --  the grounding connection is through the DIN rail.

The price for this unit is an inexpensive $32.00 -- considering the business
impact of damage to a modem, such a sum is money well spent.

To find out more on how you can benefit from an MTL solution in a variety of
applications, visit us at www.mtlnh.com, www.mtl-inst.com, and/or
www.telematic.com. You may call MTL at (800) 835-7075 for the location of
the MTL Representative nearest to you.

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