I will try to clarify the subject:
DFDR's, FDR's CVR's must have an underwater locator beacon installed to locate the recorders in case of drowning in water.
This ULB will automatically transmit a sonar signal at 37,5 KHz for a time duration of approx 30 days if the ULB willbe submerged in water.
If there is has been a crash on land, no automatically triggered locating device is coupled to the DFDR, FDR, CVR.
Deployable recorders (Voice- and Flight Data Recorders) are mostly used on military aircraft and helicopters.
This type of recorders must have ELT's (Emergency Locator Transmitter) integrated into their deployable part, which also contains the memory unit of the recorders.
Upon deployment the ELT's will also betriggered to transmit on the emergency frequencies 121.5 MHz, 243 MHz and 406 MHz. On the satellite emergency frequency (COSPAS-SARSAT) the LAT/LONG-information at the time of deployment will also be transmitted together with the specific aircraft data.
Deployment can be triggered manually or automatically, depending on the used system.
short conclusion:
- fixed installed recorders have an Underwater Locator Beacon (ULB) but no ELT installed
- deployable recorders have ELT's installed and are floatable.