Nokia 30 GSM Connectivity Terminal At Command Manual page 59

Defined values
<index> integer type values in the range of the location numbers of the phonebook
memory
<number> string type phone number of the format <type>
<type> type of address octet in integer format (refer GSM 04.08 10.5.4.7). The default
value is 145 when the dialling string includes the international access code
character "+", otherwise it is 129:
129
145
<text> string type field of the maximum length of the <tlength>
<nlength> integer type value indicating the maximum length of the <number> field
<tlength> integer type value indicating the maximum length of the <text> field
unknown/telephony
international/telephony
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