What is a GSM file?
Telephone-quality audio for voicemail and calls
GSM is a compressed audio stream that is primarily used by cell phones. GSM files are designed for telephone-quality audio use in Europe and stores audio mainly for telephone quality voice. It makes for a good balance between size of file and quality retention with data around 96KB per minute. GSM is primarily used for voicemail storage or to record phone conversations that will be played back later.
Common uses for GSM files
- Voicemail storage
- Phone call recordings
- Telephony applications
- Voicemail systems
- PBX recordings
- Call center recordings
Who works with GSM files?
Telecom engineers and IT administrators who maintain legacy PBX and Asterisk-based phone systems work with GSM files regularly, as do compliance and legal teams reviewing archived business calls. Qualitative researchers and journalists who conduct interviews over traditional phone lines may also receive recordings in this format.
GSM vs AMR: which should you use?
GSM and AMR are both speech codecs created for mobile telephony, but GSM 06.10 encodes at a fixed 13 kbps while AMR adapts across eight bitrates from 4.75 to 12.2 kbps based on network conditions. AMR is the newer 3GPP standard and delivers comparable speech quality at lower bitrates, which is why it replaced GSM full rate on 3G networks and modern mobile recorders. In practice, GSM files come from older voicemail and PBX systems, while AMR is what current phones and voice apps typically produce.
Convert AMR to text