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Community Member

SPA504G ringing problem

Hi everybody,

Our company has 3 Cisco SPA504G IP phones.

All phones have the same firmware (7.4.9c)

And all phones use power over ethernet (PoE) to power the phones.

The problem we have is that almost every day, one or two (random) phones do not ring when there is a caller.

When we reboot the phones that do not ring, the problem disappears for a few hours (seems like)

We have tried to update the firmware to the latest version and also to power the phones by AC adapter.

But the problem remains.

It is getting very annoying

Has anyone experienced this before?

If so I hope to hear your findings.


Everyone's tags (2)
VIP Blue

SPA504G ringing problem

Saying "do not ring" you mean:

the SIP comunication between phone and exchange is normal, so phone announce "ringing" to exchange, but is silent despite of it


it doesn't claim it's ringing and respond something else to exchange ?

Catch all SIP communication between phone and exchange, full syslog and debug can be helpfull as well.

Community Member

SPA504G ringing problem

Hi Danny,

Are the phones connected to an external platform throught firewall/router with nat, or are they connected to a local PBX in the same subnet.

If the phones are connected to an external platform with a firewall/router between them try this.

Go to the tab of the "ext1" tab of the phone ( assuming there is only one sip account ).

NAT Settings:

NAT Keep Alive Enable:  YES

NAT Keep Alive Msg: $PING

Share Line Appearance:

set the " Subscription Expires " down to 120.

Proxy and Registration:

set the " Register Expires" down to 120.

Hope this helps.

King regards Paul.

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