3 AAC 52.310 - Switching design standards

(a) Each utility shall maintain records for each exchange regarding the service items contained in these standards. These records must be maintained in a manner that permits audit by the commission's advisory staff.

(b) Every properly dialed call shall terminate in one of the following, unless it encounters a trouble condition:

(1) the call will progress to the number dialed, the calling customer will receive an audible indication of a ring, and the called telephone will ring;

(2) if the called line is busy, the calling customer will receive a line-busy signal (60 impulses per minute);

(3) the call will progress only part of the way through the switch train and, having reached an overflow condition, the calling customer will receive an overflow signal (120 impulses per minute) or announcement readily differentiated from a subscriber busy signal;

(4) unassigned numbers in an end office will receive a line-busy signal or an intercept announcement.

(c) Each utility shall employ a design criterion for dial-tone delay for the average busy hour of the business days of the busy season of each of its originating central office entities to enable at least 98.5 percent of attempts to receive a dial tone within three seconds. Delays of more than five percent of attempts failing to receive dial tone within three seconds indicate a need for investigative or corrective action by the utility.

(d) Each utility shall employ a design criterion for blockages and equipment failures for the average busy hour of the business days of the busy season as follows:

(1) three percent or less for overall intraoffice switching;

(2) two percent or less for access to interoffice, toll, or attendant trunks;

(3) one percent for interoffice terminating calls;

(4) one percent for groups of five or more trunks;

(5) one percent for toll trunk switching.

(e) The surveillance level for each item in (d) of this section is when five percent or more of call attempts encounter blockages or equipment failures. The surveillance level for trunk groups of four or fewer trunks is such as to provide at least one working trunk for each 12 ccs of telephone traffic load during the average busy hour of the business days of the busy season.

(f) Selection of busy hours, business days, and busy season periods must be in accordance with recognized sampling techniques approved by the commission staff, such as those specified in Bell System Traffic Facilities Practices, Continental Telephone System Practices, General Telephone Engineering Practices or the Rural Electrification Administration Telephone Engineering and Construction Manual.

Notes

3 AAC 52.310

Eff. 1/5/79, Register 69; am 3/21/2003, Register 165; am 4/20/2006, Register 178

Authority:AS 42.05.141

AS 42.05.151

AS 42.05.291

AS 42.05.331