HT802 - Silence Timeout from Silent holds


I have a HT802 that will disconnect the call after 30-40 seconds if the call is placed on hold. I know some have the Silence Timeout that can be adjusted to do that, but not able to find that setting in this model. Any suggestions where or is this model not capable to do that?


Here where you can look for the available options

Keep-alive interval Sends periodically a blank UDP packet to SIP server to keep the “ping hole” on the NAT router open. Default is 20 seconds.