Brother FAX-575 - Manual (Page 113)

EQUIPMENT ATTACHEMNT LIMITATIONS
(Canada only)
NOTICE
This product meets the applicable industry Canada technical
specifications.
NOTICE
The Ringer Equivalence Number is an indication of the maximum
number of devices allowed to be connected to a telephone
interface.
The termination on an interface may consist of any combination of
devices subject only to the requirement that the sum of the RENs
of all the devices does not exceed five.