1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 % TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%0(/.%G0G0.%47/2+G0G0!.$G0G0)3$./0%2!4)/. G0.5-“%2). G0G02/54).!.$G0G0-/“),%G0G03%26)#%-%!352%3G0G04/G0G02%$5#%G0G0#534/-%2$) they are recommended to reduce thisproblem.2 Recorded announcement2.1 It is rec
2、ommended that, at International Switching Centres (ISCs) where the trunk prefix can be detected, thecall should be blocked and automatically routed to a recorded announcement which would instruct the customer to dialthe call again without dialling the trunk prefix (see also Recommendation E.182, A.2
3、.8).2.2 An example of such an announcement is: “Please do not dial a zero after the country code when calling thiscountry. Please hang up and try your call again“.2.3 The call is blocked and the announcement given from either the outgoing ISC1)or the incoming ISC1).Theannouncement should be in the l
4、anguage of either the originating or terminating country. It is not known whether thelanguage of the originating or of the terminating country is most acceptable to the customers2).2.4 When applying this method at an outgoing ISC, care must be exercised in selecting the countries to which thismeasur
5、e is applied, as the trunk prefix which is to be blocked might be a valid trunk code for some countries. Theemployment of this measure should be preceded by a review of the pertinent information including national numberingplans and tests, as well as operator access codes, and by an explanation to t
6、he other Administrations involved of theplan to block calls having an erroneous trunk prefix.3 Customer instructions3.1 To avoid premature abandonment of attempted calls, customers should be advised to wait longer than usual fora call to be established.3.2 It is recommended that when Administrations
7、 prepare dialling instructions for their customers they emphasizethat the trunk prefix should not be dialled in the international automatic telephone service.This is necessary when the destination country conventionally writes its telephone numbers such that the trunkprefix appears with the trunk co
8、de (in parentheses). To compose a comprehensible and accurate statement can provedifficult: suitable forms are given below.3.2.1 The first form is suitable for explanation. It could be accompanied by numerical examples of completeinternational telephone numbers:_1) The exact source of the announceme
9、nts would be any suitable place, although it is preferable in traffic terms to use asource as close to the call origin as possible.2)In using the language of the originating country at an incoming international switching centre, Administrations shouldbeware of using an inappropriate language in case
10、s where calls are routed through a transit country.2 Fascicle II.2 - Rec. E.122“The trunk prefix zero that precedes the national trunk code in several countries should be omitted after thecountry code in international dialling. For example, to call Amsterdam (020) from another country, you dial 20 a
11、fterthe country code for the Netherlands, which is 31. Some countries have a different trunk prefix that should be omittedin international dialling. For example, in Finland the trunk prefix is 9, while the trunk code for Helsinki is 0; to callHelsinki (90) from another country, you dial 0 after the
12、country code for Finland, which is 358.”“Other countries do not normally include their trunk prefix with the trunk code when writing telephonenumbers: in such cases you should not omit the first digits in international calling.”An example of the use of this statement is given in Recommendation E.126
13、, Annex A.3.2.2 The second form may be more suitable in some contexts:“In many countries, a special prefix (often a zero) is normally printed in telephone numbers with the trunkcode, because it must always be dialled for long-distance calls within that country. This prefix must not be dialledwhen ma
14、king international calls to such countries. If your international call is not successful, you should check to see ifthe first digit of the (apparent) trunk code is a prefix that must not be dialled.”3.3 It is believed that widespread use of the notation given in Recommendation E.123 for national and internationaltelephone numbers would lead to a reduction in the incidence of erroneous dialling of the foreign national trunk prefix,and of other errors, in international dialling. Administrations should encourage the use of this notation.
