# Sending control messages to the remote terminal

Use these functions to send control messages to the remote terminal:

Function | Description
h324_h223SkewIndication | Sends an H.223 skew indication to the 3G-324M remote terminal to advertise any known skew between the audio and video media streams sent by the H.324 Interface.
h324RoundTripDelay | Sends a round trip delay command to the remote terminal.
h324UserIndication | Sends a user indication to the remote terminal. (The remote terminal can interpret the messages according to a proprietary scheme.)
h324VideoFastUpdate | Sends a video fast update message to the remote terminal to request that the terminal generate a complete intra-coded picture.
h324VideoTemporalSpatialTradeoff | Sends a VideoTemporalSpatialTradeoff indication to the remote terminal.
h324ModifyOutVideoChannelParam | Closes an existing video logical channel and then re-opens the channel using user-supplied logical channel parameters.
h324VendorIDIndication | Sends a VendorID indication to the remote terminal. The application can build a vendor indication identifier.