MEDC Ex ResistTel MB - Manual (Page 11)

11
Explosion Protection – Device Construction
The ExResistTel MB telephone has an unpainted casing made of
electrical-static, conductive press plant material and a stainless steel
keyboard.
The 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.
The 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. The 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.