47 CFR § 69.125 - Dedicated signalling transport.
(a) Dedicated signalling transport shall consist of two elements, a signalling link charge and a signalling transfer point (STP) port termination charge.
(1) A flat-rated signalling link charge expressed in dollars and cents per unit of capacity shall be assessed upon all interexchange carriers and other persons that use facilities between an interexchange carrier or other person's common channel signalling network and a telephone company signalling transfer point or equivalent facilities offered by a telephone company. Signalling link charges may be distance-sensitive. Distance shall be measured as airline kilometers between the signalling point of interconnection of the interexchange carrier's or other person's common channel signalling network and the telephone company's signalling transfer point.
(2) Signalling link rates will generally be presumed reasonable if they are based on the interoffice charges for equivalent special access services. Telephone companies that have, before February 18, 1993, tariffed a signalling link service for signalling transport between the interexchange carrier's or other person's common channel signalling network and the telephone company's STP are permitted to use the rates that are in place.