Yealink SIP-T58V/A

Administrator’s Guide for SIP-T5 Series Smart Media Phones
816
Step
Action
Description
The ACK confirms that User A has received
the 200 OK response. The call session is
now active.
F22
ACK—Proxy Server to User C
The proxy server sends the ACK message to
User C. The ACK confirms that the proxy
server has received the 200 OK response.