Common SIP Phone Issues and How to Troubleshoot Them

SIP (Session Initiation Protocol) phones are a key part of modern VoIP communication systems. They are efficient, cost-effective, and feature-rich, making them a popular choice for businesses of all sizes. However, like any technology, they can sometimes experience issues that affect call quality, connectivity, or functionality. Understanding these common SIP Phone issues—and knowing how to troubleshoot them—can help ensure your communication remains seamless and reliable.

No Dial Tone or Unable to Make Calls

One of the most frequent issues with a SIP Phone line is a lack of dial tone or the inability to make outbound calls. This problem is usually caused by network configuration errors, loss of internet connectivity, or incorrect SIP registration settings.

To troubleshoot, first ensure the SIP Phone is connected to a working internet connection. Check that the phone is properly registered with your VoIP provider. Sometimes, restarting the device or reconfiguring the SIP settings with the correct username, password, and SIP server details can solve the problem.

Poor Call Quality

Call quality problems like echo, jitter, or choppy audio are often the result of network issues. Because SIP Phones rely on your internet connection, any instability can impact performance. This is especially true when your bandwidth is overloaded with too many devices or applications.

To improve call quality, use a wired Ethernet connection instead of Wi-Fi for your SIP Phone. You can also configure Quality of Service (QoS) settings on your router to prioritize voice traffic. In some cases, upgrading your internet service or using a dedicated connection for voice traffic can make a big difference.

One-Way Audio

If you or the person on the other end of the call can’t hear each other, you’re likely experiencing a one-way audio issue. This is typically caused by NAT (Network Address Translation) or firewall restrictions that block voice packets.

To resolve this, make sure your SIP device is using the correct STUN (Session Traversal Utilities for NAT) server settings, which help the phone work behind firewalls. Also, ensure that the necessary ports (typically UDP 5060 for SIP signaling and a range for RTP audio) are open on your router or firewall.

Registration Failed or SIP Phone Not Connecting

A failed SIP registration means the phone cannot connect to the SIP server, making it unusable. This can happen if the SIP account credentials are incorrect or if the SIP server address is unreachable.

Double-check that your SIP username, password, and domain are entered correctly. Also, confirm that the SIP server is up and running. Some phones allow you to view registration logs, which can provide error codes or messages to help identify the issue.

Dropped Calls

If calls are being dropped after a few seconds or minutes, the problem could be related to session timers, NAT timeouts, or connectivity issues between your SIP Phone and the VoIP provider.

Make sure your SIP Phone line settings include keep-alive messages or SIP options to prevent timeouts. You may also want to extend the session expiration time if supported by your device. Updating your firmware to the latest version can sometimes resolve such issues as well.

Device Not Powering On

When a SIP Phone doesn’t power on, it could be a simple hardware issue or a problem with the power supply. For Power over Ethernet (PoE) devices, ensure the Ethernet port supports PoE and is functioning. If you're using a power adapter, test it with another compatible device.

If the device still doesn’t respond, try using another cable or port, or reset the phone to factory settings if there's a visible issue with firmware.

If you're still experiencing issues with your SIP Phone line, reach out to the experts at Aatrox Communication. We specialize in VoIP and SIP solutions, and our team is ready to assist with setup, troubleshooting, and support to keep your business communication running smoothly.

Contact Details:

Company Name: Aatrox Communication

Phone Number: 1300 645 699

Email Address: sales@aatroxcommunications.com.au

Office Address: Level 11/160 Queen St, Melbourne VIC 3000, Australia

Jennifer Winget works as a content writer at Aatrox Communications. She has seven years of experience in writing.