Showing results for 
Search instead for 
Did you mean: 

Connecting multiple devices to SPA502G Data Port

We just installed a uc520, an ESW-520 48P and 26 SPA502G phones. The phones are all PoE and we have a limited number of drops around our location, so there are multiples places where the PoE port is the only data port in the vacinity. However there are times when multiple network devices need to be attached at that location (printers, computers) and I am attempting to run the data port out of the SPA502G to a simple switch which is then connected to multiple network devices. (Because the phone is PoE, it has to be the first device inline from the data port.)

However, I have found that only one of the network devices (which one is generally a crapshoot) is able to have connectivity with the network.

The only change that has been made to the data section of the system is that a Cisco rep turned off DHCP for the data port so that our W2k3 DHCP server could still be the one to lease out the IP addresses for the data side.

Anyone know how I can get multiple devices connected through the phone without resulting to purchasing PoE switches for each location that needs one, or buying the 5V adapter?


Cisco Employee

Which switch is the phone connected to - the ESW or a UC520 switchport?  Either way, you are most likely running up against the port security configuration.  By defauly, the switchports are assigned a Smartports role of IP Phone+Desktop, which sets up the switch port to allow a maximum of only two devices to connect.  For this case, you will have to manually adjust the port configuration to relax the port security limits.




Thanks for the heads up, David. It is connected directly to the EW-520, and the EW-520 is connected through the Uplink port to the UC520.

I will try to relzx the port security limits right now.



Can you give me a hint as to where I should accomplish this? Should I be in the web interface for the ESW-520, the UC520 or the Cisco Congifuration Assitant? Or is this something I have to adjust through SSH?

Thanks man for you help. I'm a newbie in the Cisco world.


Nevermind. I found it! Cisco Configuration Assistant.

Sorry for all the replys. Your are the best! Can I send you a 6 pack of Stella?


I do like Stella.  I'll have one for you this afternoon.




Okay, so after some digging, i found that it is pretty easy to change to Smartport roles, but none of them will allow me to natively connect more than one device and still maintain use of the phone. The other choices were more or less to allow routing/switching from the PoE switch but you weren't able to maintain a VLAN for the VoIP.

I know that the phone has the ability to allow multiple devices, because when I switched it to "Other", it gave me a connection to both a Desktop and a Network Printer, but again the phone wouldn't operate.

Do you or anyone else possibly know how to add multiple connections (as you said before) manually? If I SSH into the switch, where would I make this adjustment?

Thanks again, and sorry for the serious premature posting.


Correct.  The Smartports roles don't take this situation into account.

You will have to manually modify the port settings.  I'd probably start by setting the role to IP Phone+Desktop, and then manually change the security on that port.  I don't have a switch in front of me to work out the specifics, so you'll have to play around with it a bit.  But the key bits of functionality you need include:

  • CDP to communicate the voice vlan to the phone
  • VLAN trunking to allow both the voice and data vlan through
  • QoS settings approriate for voice (hence the suggest to use a IP Phone+Desktop role as starting point)
  • Reduced port security to allow multiple data devices

Hope that helps.




Okay, so some serious weirdness.

I went into the Port Security settings tab and clicked Edit on eth1. That is where the first connection I am having issues with is located.

So what I did was uncheck the "Lock Somethingrather" tab and changed the max connections from 3 to 5. Just figured if it didn't work I would change it back.

Midway through the applying of the setting, the window froze and I had to close it. Now I have no access to the Web interface whatsoever. I can connect through telnet, and I can ping. The phone system is also still working.

Also, strangely enough, I have connections to do both devices. So I am guessing that setting worked. Unfortunately, I can no longer access the web interface of the 520-48 switch.

To make it even MORE strange, I cannot access the UC-520 web interface either. Everything pings normally, can SSH into the UC and telnet into switch.

Is this a coincidence or did I really mess something up?



p.s. I have rebooted the switch, but not the UC-520.