17. The apparatus as claimed in claim 11 , wherein said speech part conversion unit includes: a decoder configured to generate a decoded speech signal from said first code sequence with a first decoding method, when the discrimination result indicates the speech part; and a re-encoder configured to re-encode said decoded speech signal with a second encoding method and to generate said second code sequence.
11. Code conversion apparatus including at least one processor, and configured to convert a first code sequence conforming to a first speech coding scheme into a second code sequence conforming to a second speech coding scheme, said apparatus comprising: a discrimination unit configured to, via said at least one processor, input said first code sequence, and to discriminate whether said first code sequence corresponds to a speech part or to a non-speech part and generates a discrimination result; a speech part conversion unit configured to, via said at least one processor, input said first code sequence, and to convert said first code sequence into said second code sequence and to output said second code sequence, when the discrimination result indicates the speech part; a switch unit configured to, via said at least one processor, stop said first code sequence when the discrimination result indicates the non-speech part: and a non-speech part generating unit configured to, via said at least one processor, encode pre-determined one or more sound signals corresponding to non-speech including silence, noise and tones into codes by said second speech coding scheme, to pre-store the codes encoded by said second speech coding scheme, and to generate said second code sequence by reading said pre-stored codes corresponding to a value based on said discrimination result, and to output the generated second code sequence, when the discrimination result indicates the non-speech part.