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Help with RemotePhoneControl Connection Issue?

Matthew Martin
Level 5
Level 5

Hello All,

I was hoping someone might be able to help me with using this RemotePhoneControl java application...? The one created by Singlewire.

I followed all the instructions setting up the User and SNMP settings to get this working, and it DOES work for phones in my immediate network (*i.e. IP Phones connected to the same switch I am connected to). However, it does not work when I attempt to connect to a device that is connected to another switch, like devices in a remote location for example.

Right now, I have an ISR-4321 and a 2960X connected at my desk for testing and configuration. The ISR is connected to the same 4510 switch that I myself am connected to.

So if I try and connect to a IP Phone connected directly to the 4510 it works perfectly, but when I attempt to connect to a phone located on the 2960X, I get an error that it cannot communicate with the IP Phone. I figured since it could just be a basic communication issue with something on the ISR, maybe someone here could help.?

If I connect a laptop on the same 2960X that the IP Phone is on (*PC=10.18.1.x, Phone=10.18.2.x), I still cannot connect to that phone. Running Wireshark on that laptop while attempting to connect to the IP Phone on the 2960X, bizarrely shows no packets at all. But, if I look at the Packet Logs on Symantec, it does show an attempt to communicate with the IP Phone's IP Address.... But, there is no return response from the phone. I disabled all Firewall rules on Symantec, but that didn't seem to change anything. I can ping the phone just fine from the PC, so at least I know I can reach that phone with Pings... Also, nmap shows that port 80 is open on the phone in question.

*I have attached a screenshot of Symantec's Packet Logs, and in it you can see Outgoing requests to the Phone, but there is no response...

Any ideas what could be blocking the communication between the laptop and the IP Phone? Seems to me that there is something on the ISR that could be blocking the communication.

Any thoughts or suggestions would be GREATLY appreciated!

Thanks in Advance,

4 Replies 4

Chris Deren
Hall of Fame
Hall of Fame

What phone model are you trying to connect to?

The new models such as 78XX and 88XX do not work with SingleWire remotephonecontrol.

Hey Chris, thanks for the reply, much appreciated!

I am trying to connect to 7941G, 7961G and 7962G...

I'm not sure what I did but I attempted this again, from my PC which is NOT connected to the 2960X, but still can reach the IP Phones that are connected to that switch. And this time I was able to see some data in Wireshark... Not sure if the issue was the filter I was using, because when I re-added the filter and applied it after I saw the packets from the IP Phone, they disappeared and removing the filter I could see them again. So now that I could see that packets, at least I know they are talking... I got this Error message below from the RemotePhonesControl app:

"RemotePhoneControl is having difficulty communicating with the phone. You may need to check the settings. Unable to read phone screen image, image in an unregistered format."

Any idea what that error means? In Wireshark I can see that it downloads the XML file from the phone containing all it's information, i.e. And the window that opens that is supposed to display the phone, does show the correct model number. So I'm not sure the issue...

Any thoughts on that error?

Thanks Again,

Is Web Access enabled on the device?

Can you browse to this address from the PC you are running the app on?

Is SNMP properly defined on the application to match the SNMP on CUCM server?

Hey Chris, thanks again for the reply, much appreciated!

Ok, so I figured out the problem, and it was kind of a bit of an oversight on my part. When I first setup the Application User for this I only associated MY IP Phone and a couple others to test with... So I am now Associating all the 79XX phones to my App user and will do some tests.

I'll comment back once I've added them all to the user and I'll let you know if it's working.


After just adding all 79XX IP Phones to my Application User for RemotePhoneControl, I can now view/control all associated IP Phones...

Thanks Again,