asterisk-core-sounds-en-gsm 1.4.21-1 (i386 binary) in ubuntu precise

 Asterisk is an Open Source PBX and telephony toolkit. It is, in a
 sense, middleware between Internet and telephony channels on the bottom,
 and Internet and telephony applications at the top.
 .
 Asterisk includes a set of standard sound files in various formats. This
 package contains the core part of that collection in English (US, by
 Allison Smith) in raw gsm-fr format (Compressed. Takes relatively little
 space. playable with sox).
 .
 This package also provides the 'en' and 'en_US' sound directories through
 alternatives and hence is required by packages of other formats.