(1) For the purposes of this Part, if a carriage service provider charges an eligible customer for eligible local calls made using a standard telephone service supplied to the customer, the provider gives the customer an untimed local call option if, and only if, the service is supplied to the customer on terms and conditions under which:
(a) the customer may choose, on connection of the service, to have the charges for eligible local calls that are made using the service worked out on an untimed basis; and
(b) if the customer chooses as mentioned in paragraph (a)--the carriage service provider must not work out the charges for such calls in any other way except with the customer's written consent; and
(c) if the customer:
(i) does not choose as mentioned in paragraph (a); or
(ii) consents to having the charges for such calls worked out otherwise than on an untimed basis;
the customer may later give the carriage service provider a written notice to the effect that the customer wishes the charges for such calls to be worked out on an untimed basis; and
(d) if the customer gives the carriage service provider such a notice--the carriage service provider:
(i) must, in respect of the earliest practicable period beginning after it receives the notice, work out the charges for such calls on an untimed basis; and
(ii) must not, in respect of a period after the period referred to in subparagraph (i), work out the charges for such calls in any other way except with the customer's written consent.
Note 1: Eligible customer is defined by section 110.
Note 2: Untimed basis is defined by subsection (2).
(2) For the purposes of this section, charges for eligible local calls are worked out on an untimed basis if, and only if, the charges for those calls are worked out by reference to the number of such calls made during a particular period, regardless of how long each call lasted.