hI,

I am a non-network newbie struggling with network issues that are way above my pay grade and would appreciate some/any advice :

installed equipment is

TP-LINK ER-6020 1unit

CISCO SG220-26 SWITCH first unit

  desktop 5 unit, print 3 unit, voip 6 unit

cisco sg220-26 switch second unit

   CISCO AP WAP121 2 unit

   CISCO AP WAP150 1 unit

    wireless ip cam 3 unit, ip cam 3 unit, tablet 4 unit

    desktop 10 unit 

    voip 1 unit and 

The problem is that the voip connected to the first switch suddenly hangs up if the call is longer than 5 minutes.

No settings

Thanks