Motorola T1I Series Manual page 39

Technical Information
How many telephones can I have? All items of telephone equipment have
a Ringer Equivalence Number (REN), which is used to calculate the number
of items which may be connected to any one telephone line. Your T1I has a
REN of 1. A total REN of 4 is allowed. If the total REN of 4 is exceeded, the
telephones may not ring. With different telephone types, there is no guarantee
of ringing, even when the REN is less than 4.
Any additional handsets and chargers that you register have a REN of 0.
Connecting to a switchboard
This product is intended for use within India for connection to the public
telephone network.
Flash
You may need to use the flash function if you are connected to a switch.
Contact your PABX supplier for further information.
General information 39