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Help! QuickSet C20 doesn't appear as a device on network

I'm trying to set up our new C20 video conferencing system. In trying to figure out why it's not working, I've isolated the problem to the fact that the codec is not registering at all as a device.

I've run an ethernet cable from the C20 into my router just to see if it shows up. When I inspect the devices wired into the router, the C20 does not appear. When I disconnect the cable from the C20 and reconnect it to my laptop, my laptop shows up as a connected device. (My printer also shows up as a connected device.) This means there's nothing wrong with the cable itself.

In other words, the C20 is not appearing as a device; it's invisible on my network. Yes, the C20 is turned on, of course. I see the blue cloud screen and myself in the corner of the screen.

Any idea why the C20 isn't showing up? Any help is greatly appreciated.


Help! QuickSet C20 doesn't appear as a device on network


as far as I know, the C20 will only attempt to obtain an IP address via DHCP during boot up, which means that if you connected the network cable after the codec had finished booting, you will not see the C20 requesting an IP address via DHCP.

I suggest you try to reboot the C20 with the network cable connected, the C20 should boot up and pull an IP address from DHCP (Assuming that your router has its DHCP server function enabled). The IP address should be displayed in the topmost section of the screen once the codec has finished booting.

- Andreas

Community Member

Help! QuickSet C20 doesn't appear as a device on network

Hi Andreas-

Thanks for the response. We have a static IP, so I'm not sure DHCP even applies to me. So when I tried DHCP, I do indeed get an internal IP address to show up on the router ( for my C20. But it won't allow me to call or receive.

I guess the good news is that I can now see that the C20 is alive when trying DHCP and I understand why it doesn't show up when plugged it into the router the first time since there could only be one device assigned to my static IP.

But then I disconnected my router from the modem and plugged the C20 directly into the modem, it still wouldn't work. (Now the C20 is the only device connected to the modem.) I know it doesn't work because I'm calling a Cisco test IP ( and nothing happens. H.323 and SIP are disabled. I'm trying to test with the simplest configuration possible.

I know at this point, it could be one of hundreds of different configurations that may explain why it's not working. That's one of the frustrations with the C20: there is absolutely no user feedback as to why it doesn't work. I don't know if it's because packets aren't getting sent out; or not receiving; or security settings are blocking transmissions; or if the other side is turned off or busy. Nothing.

Any suggestions as to what to check next or how best to debug?


Help! QuickSet C20 doesn't appear as a device on network


if the C20 is not registered to a VCS Expressway, and if the C20 is located behind a NAT router and assigned with a private IP address, you need to configure the H323 NAT settings on the C20 itself as well as set up port forwarding rules towards the C20 in your NAT router.

The test IP you mention does not seem to work from my location either, so I would suggest that you perform further tests with a different, known working address/alias.

As for troubleshooting the issue, if you are familiar with analyzing network traces, you could get a tcpdump from the C20 and open it in Wireshark, as this would provide a lot of information about what the C20 is attempting to do, and possibly why the call is failing.

I would however suggest that you raise a TAC case if you are unable to get things to work after configuring NAT on the C20 and on your router, so that appropriate logs can be obtained and analyzed.



Re: Help! QuickSet C20 doesn't appear as a device on network

You want to read the release notes and admin guide.

It might be handy if you have yourself a simple understanding of what you want to do and then check how it is done.

First of all the system only uses h323 or sip to call out, if both are disabled, ... not a real chance to succeed here.

You say you are on a private ip, this means NAT is involved, for this I would strongly recommend a

VCS-E registration as this offers the best firewall traversal you can get for your device.

If you don't have that the minimal setup without a VCS-E behind nat it would look somehow like that:

(if I even got you right here as you don't reveal much and the rest looks a bit cryptic to me :-)

Also reboot the endpoint to make sure you get a new ip. Some provider don't hand our public ips,

some limit it to a specific mac, ...

Did you check that your c20 network connectivity is ok when you connect it directly to the modem?

Minimal config for a clean system on a public ip shall be

* ip connectivity with public ip

* set passwords on the system! (even just for testing) (see admin guide)

* enable h323 (xConfiguration NetworkServices H323 Mode: On)

* enable direct h323 mode (xConfiguration H323 Profile 1 CallSetup Mode: direct)

* place your call

If you want to have it behind NAT its more like this:

* ethernet / ip / Internet connectivity (this seems to be ok now)

* enable 1:1 nat from the public ip address of the router to the IP of the endpoint

* enable h323 (xConfiguration NetworkServices H323 Mode: On)

* enable direct h323 mode: (xConfiguration H323 Profile 1 CallSetup Mode: direct)

* check that sip is disabled and/or h323 is the default protocol (xConfiguration Conference 1 DefaultCall Protocol: H323)

* enable NAT mode ( xConfiguration H323 NAT Mode: on

* define the external address (xConfiguration H323 NAT Address: "")

Andreas: it would be quite useful if the dhcp process would respawn if a link up change on the network interface is detected.

Please remember to rate helpful responses and identify


Re: Help! QuickSet C20 doesn't appear as a device on network

Hi get back to basics. Static assign your laptop with and your codec with .2 use a cross cable and see if you can ping/web into the codec.

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