Am not sure it would work on YateBTS. It would work on Yate. So i think basic operation may be same.
[extra]
call.cdr=120,operation
[call.cdr]
;Using CDR Opertation for to record a Call once answered
update=if ${status}^answered$=if ${direction}^incoming$=enqueue chan.masquerade;\
message=chan.record;id=${chan};\
both=wave/record//var/spool/yate/tmp/${caller}_${called}_${billid}.gsm;\
format=2*slin
