Technical
Technical information
Choosing a position
Your DF450 should be kept clear of dust, moisture, high temperature and vibration and should not be exposed to direct sunlight. Don’t install it close to radiators or
Warning
The apparatus is only designed to be operated in a normal office or domestic environment where the relative humidity does not exceed 60%. It should not be used in bathrooms or near water.
Connecting to the UK network
DF450 is tested and approved for connection to the UK network, provided that it is used in accordance with the guidelines in this booklet.
Approval number
BABT Certificate Number/Approval Number for the DF450 503727 APPROVED for connection to telecommunication systems specified in the instructions for use subject to conditions set out in them. CE compliant to 89/336/CEE (EMC Directive)
Approval for use
This apparatus has been approved for use with the following facilities:
Storage of telephone numbers for retrieval by a predetermined code. (If problems occur, verify stored number).
Automatic call initiation.
Use on a PBX which returns secondary proceed indication. Operation in the presence or absence of initial or secondary proceed indication.
Automatic dialling facilities.
Automatic storage of last number dialled. Automatic repeat attempt facilities.
Auto clear from the originating end. Series connection facility.
Call progress monitor.
You may connect it:
•to direct exchange lines:
•to extensions with new plug and socket arrangements provided with these direct exchange lines;
•to compatible switchboards.
You may NOT connect it:
• to shared service (party) lines.
The connection to the telecommunication system must be unplugged before the earth is disconnected. The connection to the telecommunication system must not be hardwired.
This apparatus may be used on telecommunications systems employing loop disconnect or MF signalling.
Any other usage will invalidate the approval of the apparatus if, as a result, it then ceases to conform to the standards against which approval was granted.
How many phones you can have
Your exchange line provides only a small current to make your telephone ring. Although you may have any number of sockets it is important to limit the number of telephones and other items of apparatus connected to the line by these sockets. This ensures that each telephone will receive enough current to ring.
Every telephone or item of apparatus has a Ringer Equivalence Number (REN)
In most cases a standard line should provide enough current for two or more telephones or items of apparatus, if the RENs add up to no more than 4.
DF450 has a REN of 3. Any telephone provided by BT may be assumed to have a REN of 1 unless otherwise stated on the base. Even where the number of telephones has been limited, there is no guarantee that the different types of telephone on the same line will ring.
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