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Community Member

SF 300-24P uplink problem

Dear Team,

We bought a cisco POE Switch (Cisco SF 300-24P) from a reseller before two months, and we are facing a problem when we connect just an uplink on Telephone network and it is a standalone network and there is no Vlans connected to this network, the other two switches on this network are LINKSYS SRW224P (Old Product), and the problem is when we dial from POE phones like Linksys SPA922; the tone gone and we can’t hear the one who we are calling and he don’t hear us, but when we disconnect this uplink cable from the Switch above every things come back normal.

Please advise.

Many thanks

Community Member

SF 300-24P uplink problem

it would be good to see a topology of your network to help troubleshooting.

is the uplink between your switches? if so, you could have a loop in your network,

do all the activity lights light up on your switches whan you plug in the uplink?

Verify all the cables between the switches and make sure you don't have a loop,

virtual server hosts with multiple nics, unmanaged switches and hubs can also cause this.

You can also look in the logs to see if there are spanning tree errors, or

look at spanning tree status to see if there are ports that have a 'blocked' state, that would indicate spanning tree has shut down a port,

if the uplink is to the telephone network... is this an analog line? 

you say standalone network, so I assume it's not an ethernet cable...

Community Member

SF 300-24P uplink problem


Did you manage to find a solution? We are facing the same symptoms with the same devices: SF300 switch and SPA922 IP phones.

Thank you in advance,

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