1 1
E xplosion Protection – Device Construction
T he E xSafeTelMB telephone has an unpainted casing made of
electrical-static, conductive press plant material and a stainless steel
keyboard.
T he casing consists of a box shaped lower part, in which a tub is
integrated to hold the electronic system, as well as a curved cover with
a keyboard.
T he cover is pressed under the medium layer of a surrounding seal with
four screws on the casing lower part and forms the non-secure and
secure connection space. T he electronic system conductor board is
located in the tub from the casing lower part, which is completely
embedded in the compound.
Non-secure connection clamps with increased security:
From the casting, a 4-pin connection clamp series (See connection plan
on page 18 ) comes out in increased security, to connect the non-secure
telephone network (A, B), clamp 13 and 14 as well as for the connection
for an optional, external, explosion protected second alarm (Bell shunt1 ,
Bell shunt), clamp 15 an 16 .
