1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 % TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%0(/.%G0G0.%47/2+G0G0!.$G0G0)3$./0%2!4)/. G0G0.5-“%2). G0G02/54).!.$G0G0-/“),%G0G03%26)#%$)3#/52!%-%.4G0G0/ disconnecting when the limit is reached; offering no lengthy information without charge.4 Abateme
2、nt4.1 When frivolous calls can be identified as originating from the network of a particular Administration, theAdministrations concerned should arrange bilaterally to implement the most appropriate prevention and abatementmeasures for the particular case. This bilateral arrangement may include meas
3、ures not recommended for generalapplication.4.2 In general, vacant subscriber number announcements should not be replaced by non-standard tones to reducefrivolous calling because the use of unfamiliar tones might cause increased repeat attempts by serious callers. Whereparticular numbers have been i
4、dentified as the targets of frivolous callers, replacing announcements by tones for alimited period should not degrade the service for serious callers. For this purpose only, a special information tone isrecommended._1)The problem was first discovered in Japan after KDD noticed a large number of cal
5、ls lasting longer than one minute without ananswer signal being returned.2)Where the signalling systems permit, the use of a backward unallocated-number signal will allow an appropriate tone orannouncement to be returned to the caller according to Recommendation E. 181, 2.2 Fascicle II.2 - Rec. E.12
6、44.3 When frivolous calling has been identified as causing quality of service problems, it is desirable to detect thecalls and direct them to an appropriate announcement as close to the calling subscriber as practicable. Theadministrative and technical difficulties of updating such arrangements for
7、changes in many different numbering plansmake the incoming international switching centre the practical limit in most cases. By bilateral agreement, however,frivolous calls might be blocked at the outgoing international switching centre instead.4.4 In accordance with Recommendation E. 231, no charge
8、 should be made for calls to subscribers whose servicehas been suspended, cancelled or transferred. When calls to certain of these out-of-use numbers have been identified aspredominantly frivolous, the provisions of Recommendation E. 231 may be temporarily ignored for only the particularnumbers invo
9、lved, until the problem is abated3), and subject to the agreement of the Administrations concerned. Callsto these numbers would then have an answer signal returned and would be charged4). Calls to unassigned numbers maybe handled similarly. This measure would be immediately effective when frivolous calls originate from payphones._3)Administrations should take care not to apply this measure to non-frivolous telephone calls.4)Some exchanges may require the addition of a function to handle such calls in this manner.
