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Why does mobile network disconnect during long voice calls

You start a normal phone call, everything sounds clear, and then somewhere after several minutes the call suddenly drops. Sometimes the signal bars briefly disappear. Other times the call switches to silence before ending on its own. When you call back, it works again — until the same thing happens later.

This pattern usually isn’t random. Long voice calls place sustained demand on the cellular connection, and certain network or device conditions only begin to fail after the connection has been active for a while.

What Usually Causes It

Most call drops during long conversations come from one of these situations:

  • The phone moves between cell towers and fails to hand off cleanly.
  • VoLTE or 4G/5G calling becomes unstable in weak coverage areas.
  • Network power management interrupts the radio connection.
  • The carrier temporarily reassigns bandwidth during congestion.
  • SIM card or modem firmware struggles to maintain long sessions.

Short calls often work because the connection ends before instability appears.

Fixes to Try

Keep the Phone Locked to a Stable Network Mode

Phones constantly switching between 5G, 4G, and sometimes 3G can trigger call drops during long sessions.

  1. Open Settings.
  2. Go to Mobile Network or Connections.
  3. Select Preferred Network Type.
  4. Temporarily set it to 4G/LTE only.

4G voice calls are often more stable than automatic 5G switching, especially indoors or while moving.

Disable Wi-Fi Calling Temporarily

If Wi-Fi signal quality fluctuates, the phone may attempt to transition between Wi-Fi calling and cellular calling mid-conversation.

  1. Open Settings.
  2. Tap Wi-Fi Calling.
  3. Turn it off and test another long call.

Reset Network Settings

Corrupted carrier profiles or modem settings can interrupt long-duration connections.

  1. Go to Settings → General Management (or System).
  2. Select Reset.
  3. Choose Reset Network Settings.

This removes saved Wi-Fi networks but often clears hidden connection conflicts.

Check Signal Stability, Not Just Signal Strength

Full bars don’t always mean a stable tower link. If calls drop in one specific location, the phone may be bouncing between nearby towers.

Try making a long call:

  • Near a window
  • Outdoors
  • Without moving around

If the problem disappears, tower handoff instability is the likely cause.

Update Carrier Settings or System Software

Manufacturers regularly release modem updates that improve long-call stability.

  1. Check System Update in Settings.
  2. Install any available updates.
  3. Restart the phone after updating.

Reseat or Replace the SIM Card

An aging or slightly damaged SIM may maintain short data sessions but fail during extended voice connections.

  1. Power off the phone.
  2. Remove and clean the SIM gently.
  3. Reinsert and test again.

If drops continue, request a replacement SIM from your carrier.

Alternative Solution

If long calls are essential for work or meetings, using a reliable internet calling app over stable Wi-Fi can bypass cellular tower handoff issues entirely. This helps confirm whether the problem is network-related rather than hardware-related.

Once calls remain stable after adjusting network mode or resetting connection settings, the underlying interruption is typically resolved.