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Chapter 7 - BABT Requirements7.1.1 European Low Voltage Directive
When correctly installed and maintained, the modem will present no
hazard to the user. When correctly installed the modem will be connected
to the PSTN or a PW and to a Data Terminal Equipment (DTE), whose
modem connections comply with CCITT recommendation V28. The DTE
connections are therefore taken to be safe voltages (less than ± 30 volts).
The main power source shall be installed near to the equipment and shall
be easily accessible. The plug that connect to the apparatus to the main
power supply must be fitted with a 5A fuse that complies with BSI1362.
Ports which are capable of connecting to other apparatus are defined as
SELV. To ensure conformity with EN 41003, ensure that these ports are
only connected to ports of the same type on other apparatus.
7.1.2 Compliance with BS6305 Clause 6.2, BS6320Clause 7.2, and BABT/SITS/82/005S/D
a. The modem is suitable for connection to the Public Switched Telephone
Network (PSTN) provided by British Telecommunications plc or
Kingston Communications (Hull) plc. Circuit supply by British
Communications, Mercury Communication, or Hull City Council. Only
direct exchange lines may be used, not shared service.
b. The modem is suitable for household, office, and similar general indoor
use. It is not suitable for use as an extension to a payphone.
c. BT lines supplied must support either loop disconnect or multifrequency
tone signalling.
d. REN (Ringer Equivalence Number).
The REN value of a unit is calculated from 3/n where n is the total number
of units which can be connected in parallel which will still cause the
standard bell (as defined in BS6305 Appendix D) to ring.
REN values of less than 0.3 cannot be assigned.
REN = 1