Diagnostics Tools
If you are experiencing network problems or voice quality issues, you can perform network diagnostics using the Ping or Trace Route tools.
You can run the tools directly from your CP925/965/935W phones for the most relevant measurements. You can specify any IP address, including your local network. But it is much better if the test measures a longer network distance. Two popular IP addresses to use are Google's DNS at 8.8.8.8 or 8.8.4.4.
Finding the IP Address of your Phone
To find out the IP address access the Control Center by swiping down from the top of the screen or by tapping 
on the bottom of the idle screen.
Select Status>General (on the CP965 tap Settings first.)
With this address you can perform the diagnostics from any computer or mobile device to see if your phone is reachable on the network or where there may be a problematic point in reaching it.
The Ping Tool
The Ping tool sends a sequence of small data packets to an IP destination you specify. This is generally used to check the validity and availability of that address. But the tool also measures the latency and jitter on the network, meaning the time it takes for the packet to travel between your phone (or a computer) and the IP address and back. Values under 150 milliseconds are generally acceptable for domestic VoIP calls.
The Ping tool will also show the number of packets it transmitted and received back. Loss of packets (essentially a loss of voice information) is indicated if the numbers are not equal and fewer packets are returned.
These measurements allow you to compare and select the most ideal configuration for your phone choosing between static IP and DHCP and between Wi-Fi and wired connection (a wired static IP should generally provide the fastest performance.)
The Trace Route Tool
Like the Ping tool, the Trace Route tool also checks the time it takes data packets to travel back and forth from your phone (or a computer) in milliseconds. But while the Ping tool only shows the results in relation to the recipient IP, Trace Route breaks it down and displays information for every device, router, host, and network point on the way to the recipient IP.
To illustrate the difference, you can think of a train schedule as an example. In this regard, Ping shows the time it takes to travel to the final stop and back while Trace Route shows the travel time (back and forth) for each stop along the way.
With this information you can get a sense and isolate points where there is an actual problem with the network connection (where the train in our example slows down or even stops).
Keep in mind that with each stop, the measurement time will increase as the packets physically cover more travel distance. What should get your attention are values over 150 milliseconds where voice quality degradation becomes increasingly noticeable.
Another thing worth noting is that some routers can ignore or reject Trace Route packets resulting in a "Request timed out" message. This can also be due to an actual problem with the particular "network stop", but usually it just indicates a lack of available information for it.
Running the Diagnostics
To run network diagnostics on the CP925/965/935W:
- Access the Control Center by swiping down from the top of the screen or by tapping
on the bottom of the idle screen. - Navigate to Features>Diagnostics>Network (on the CP965 tap Settings first.)
- Do one of the following:
- Select Ping and enter an IP address or URL in the relevant field.
- Select Trace Route and enter an IP address or URL in the relevant field.
- Select Ping and enter an IP address or URL in the relevant field.
- Select Start.
- The screen will show the results for the test you selected.