A. The utility shall have facilities which will allow 98.5 percent of all calls placed to receive a dial tone within 3 seconds.
B. As a minimum acceptable level of performance, 95 payment of attempts during the average busy season busy hour shall receive a dial tone within 3 seconds.
C. The busy season shall be the period composed of those months of highest load for the particular service being considered. The busy season shall ordinarily include 3 months, not necessarily consecutive. The beginning of the "month" may be other than the beginning of the calendar month, if good cause and consistency can be shown.
D. The busy hour shall be the 2 consecutive half-hours during which the greatest volume of traffic is handled in the central office. Different days of the week may have different busy hours, but the hour selected for any day shall be used on that day of the week for the entire busy season.
E. Reasonable Call Completion Rate.
(1) Reasonable call completion rates to establish "minimum acceptable levels of service", based on observed results of properly dialed calls in all offices sufficient in size to provide a statistically reliable service measurement sample, shall be:
(a) Local calls by customers94 percent completions;
(b) DDD calls by customers(outgoing trunks) 94 percent completions;
(c) DDD calls by customers(incoming trunks) 96 percent completions.
(2) For purposes of computing the completion rates suggested, properly dialed completed calls shall include:
(a) Reaching the number that was dialed;
(b) Reaching a busy condition at the dialed number;
(c) Reaching a "ring, no answer" at the dialed number;
(d) Terminating the call before it has routed to the dialed number;
(e) Reaching intercept correctly.
F. Outgoing toll trunks (dial 0, 0+, and 1+), toll completing trunking, and final route inter-toll trunking shall be designed so that not more than 1 percent of the attempts to connect to a toll trunk in the busy season, busy hour will encounter an all-trunks busy condition.
G. As a minimum acceptable level of performance, incoming matching loss may not exceed 5 percent in the average busy season, busy hour.
H. Recognized engineering practices shall be utilized to determine equipment provisions required to meet the objectives mentioned in this regulation.