Investigating Possible Causes of Voice Quality Issues
Microsoft Office Communications Server 2007 and Microsoft Office Communications Server 2007 R2 will reach end of support on January 9, 2018. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.
Typically, Enterprise Voice quality issues are reported by users. Investigations of voice quality issues almost always start from examining the user’s report. Interviews with the user are often required to gather additional information about the user’s experience. The following table describes the most common issues that are reported by users and the most likely cause of each issue: the device, the network, or the PSTN. You can use the following table to begin your investigation of the most likely source of the issue.
Note
It is possible to identify and resolve some issues before they become user-reported issues. Routine monitoring and evaluation of events can facilitate early identification and resolution of potential issues. For details, see Heading off Potential Problems with Enterprise Voice.
Table 4. Possible causes of voice quality issues
| Issue | Possible cause: Likelihood | Explanation |
|---|---|---|
Low volume |
Device : High PSTN: Medium Network: None |
Device: Volume setting is too low or person speaking is too far from microphone. PSTN: Phone volume is too low, IP/PSTN gateway gain settings are too low. |
Missing words in conversations |
Network: High Device: Medium PSTN: None |
Network: Packet loss or jitter. Device: Microphone volume is too low, or person speaking is too far from microphone or speaking too softly. |
Distortion |
Network: High Device: Medium PSTN: None |
Network: Packet loss or jitter. Device: Audio enhancement hardware or software is interfering with audio processing in Office Communications Server, microphone or speaker is defective, or volume setting is too high resulting in clipping. |
One-way audio |
Network or PSTN: Medium Device: Medium |
Network: Improper network routing or severe one-way loss. PSTN: Defective or incorrectly configured gateway, or errors in codec configuration. Device: Audio input or output is muted or volume is turned down to 0. |
Long call setup time |
Network, PSTN, or Device: Medium |
Network: High latency, IPSec, or packet loss. Device: Slow device initialization. PSTN: Slow PSTN signaling. |
Audio delays |
Network: High PSTN or Device: Medium |
Network: High latency or traffic shaping. PSTN: Long PSTN segment, calls involving mobile phones or PSTN audio conference bridges. Device: Signal processing or buffering is slow. |
Echo |
Device: High PSTN: Medium Network: None |
Device: Incompatible devices (for example, an omni-directional microphone that picks up sound from the speakers, resulting in feedback) or devices that come as a set but are not used together (for example, a microphone and speaker that are designed to work together, but are not used together), microphone not well isolated from speakers, multiple microphones in the same room. PSTN: Limited or no echo cancellation on phone line or PSTN audio conference bridges. |
Loud static or background noise |
Device: High Network or PSTN: None |
Device: device drivers, incorrect placement of device, faulty ground or cabling. |
After you have identified the likely source, see the appropriate troubleshooting topic for information about how to resolve the issue, as follows: