Editing SimTX API/Control session (section)

== Monitoring a transmitter ==
[[SimTX API/Packets/StartMonitor|StartMonitor]] streams the complex baseband a transmitter is producing, after its modulator and amplifier model but before the antenna and propagation.

Only transmitters belonging to the same account can be monitored, so the control session must be authenticated. Monitoring requires <code>catalog.publish</code>: the account service issues <code>control</code> tickets only to credentials with that permission. See [[SimTX API/Game tickets#Roles|Game tickets]].

The <code>session_id</code> to monitor is the one in the transmitter's own [[SimTX API/Packets/SessionStatus|SessionStatus]], or a <code>LiveSession.session_id</code> from the station list. The server confirms with [[SimTX API/Packets/MonitorAck|MonitorAck]] and then streams [[SimTX API/Packets/MonitorBlock|MonitorBlock]] frames; [[SimTX API/Packets/StopMonitor|StopMonitor]] is confirmed by a MonitorAck with <code>active = false</code>. When the transmitter goes off the air, the server sends [[SimTX API/Packets/MonitorEnd|MonitorEnd]].

Monitor blocks share the control session's output queue (64 frames or 8 MiB). A client that does not read them fast enough has its control connection closed.