Contact gets busy signal when calling me

When you make a cellular 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.

Caller tunes, also known as ringback tones, are a feature offered by mobile carriers. These tunes are activated and configured directly from the subscriber's device using the carrier's app or service. Once a caller tune is set, it is stored on the carrier's servers, not on the subscriber's phone.

When someone attempts to call the subscriber, the process works as follows: the carrier's system identifies the caller tune assigned to the subscriber's number and plays it through the carrier's infrastructure (such as the cellular tower or central switching system). The tune is streamed to the caller as they wait for the subscriber to answer the call.

It is important to note that this feature is entirely managed by the carrier and is independent of the subscriber's phone or operating system. For example, whether you use an iPhone or any other device, the caller tune functionality remains a carrier-specific service. The subscriber's device simply acts as a means to select or configure the tune through the carrier's interface, but the actual playback and storage of the tune occur within the carrier's network.

Also, when you hear; Phone Switched off, Not Answering, Engaged, Out of Network coverage area, or Not reachable are messages conveyed to you from your Carrier's tower and not from your iPhone.

When a caller calls a number your Carrier's network tower tries to reach you on your device and tries to get the status of your mobile. What is fetched and what is recorded is totally by the carrier's server.

Please contact your Carrier.

All tones are from the Carrier's Tower none of it are from the iPhone or any phone for that matter

• Dial tone.
• Ringing tone.
• Busy signal.
• Reorder tone.
• Disconnect tone.
• Special information tone.
• Off-hook tone.

Read this for better understanding Call-progress tone - Wikipedia

That would be an issue with your carrier. Contact them for help.