TCP Input mode receives raw PCM audio from AutoCast over a local network connection. This is the primary production mode for TuneTracker stations: AutoCast handles music selection, scheduling, cart playback, and all the complex automation — and SignalCaster receives the mixed audio output and puts it on the stream.
SignalCaster opens a TCP listener on a fixed local port. AutoCast connects to this port and sends a short handshake (sample rate, channel count, and sample format), then immediately begins streaming raw PCM audio frames. SignalCaster acknowledges the handshake and starts forwarding the audio to the AAC encoder and onward to the stream.
The connection is one-to-one: SignalCaster only accepts one TCP client at a time. If a second client tries to connect while one is already active, SignalCaster drops the old connection and accepts the new one.
In the Settings drawer, set Audio Source to TCP Input (AutoCast). There are no additional fields to configure on the SignalCaster side — the port is fixed. On the AutoCast side, configure its SignalCaster output to point to localhost and the port SignalCaster is listening on (shown in the Activity Log at startup).
SignalCaster starts the TCP listener immediately when you switch to TCP Input mode, even before you start streaming. AutoCast can connect any time and SignalCaster will receive audio — it just won’t send it anywhere until you click Start Streaming.
The status line on the dashboard shows the TCP connection state: Connecting to source… while waiting for a client, and Connected to TCP Input once AutoCast has connected and the handshake is complete. The VU meters animate when audio is actively flowing.
If the TCP client disconnects while SignalCaster is in the middle of a live stream, SignalCaster automatically fills the gap with silence so the stream doesn’t stall. As soon as AutoCast reconnects, real audio resumes. Your listeners may hear a few seconds of silence, but the stream stays connected to the server throughout.
SignalCaster reads the sample rate from AutoCast’s handshake and configures the AAC encoder to match. You don’t need to set this manually. The sample rate in use is logged in the Activity Log during the handshake phase.
AutoCast writes the currently playing track to a text file in your Station folder at Misc/System/current_song.txt. SignalCaster polls this file periodically and pushes track changes to the stream (Icecast metadata or RTMP video overlay) automatically. Configure exactly how the text is parsed and displayed in the Now Playing Overlay settings.