Unable to hear ringing sound when calling on my iPhone 15

When you make a call, the communication process is primarily managed by your carrier's network infrastructure rather than your iPhone.

Here's how it works:

1. Call Initiation: When you dial a number and press the call button, your iPhone sends a request to the carrier's nearest cell tower.
2. Network Handling: The carrier’s network processes the request and tries to establish a connection with the recipient's device by routing the call through its infrastructure.
3. Status Check:
   1. If the recipient's phone is switched off, the network detects this and sends you a message such as "Phone switched off."
   2. If the line is busy, you may hear an "Engaged" tone.
   3. If the phone is unreachable (out of network coverage area or disconnected), the network conveys this status to you.
   4. If the recipient doesn’t answer the call, the network determines that based on no response from their device.
4. Ringing Tone: Even the ringing sound you hear when the call is trying to connect is generated and relayed by the carrier's network, not your iPhone or the recipient’s phone. This tone is purely a network-generated indicator that the call setup process is ongoing.
5. Minimal Role of the iPhone: Your iPhone essentially acts as a sender and receiver of the communication request and handles user interface elements such as dialing, displaying call status, and receiving tones. The actual call status messages, including the ringing tone, are determined and conveyed by the carrier's network.

If you're encountering issues with specific call status messages, connection problems, or abnormal behavior during calls, the carrier is the appropriate point of contact, as these issues are rooted in the carrier's network or service rather than your device.