What method of call sign identification is required for a station transmitting phone signals?

The requirement for call sign identification during phone transmissions involves sending the call sign using a CW (Continuous Wave) or phone emission. This method aligns with FCC regulations that mandate operators to identify their stations periodically during communications.

When using phone (voice) transmissions, the operator must state their call sign clearly and audibly, ensuring that it can be understood by other operators. This requirement applies whether the operator is transmitting in voice or using CW techniques, which is a method often associated with Morse code. By allowing the identification through both voice and CW, the rule accommodates varied operating methods and preferences among amateur operators.

The other options include indicators or specify a singular transmission mode which does not fully encompass the identification requirement as mandated by the regulations. Hence, the inclusion of both CW and phone emissions provides the flexibility needed for effective identification during amateur radio operations.