## ConnectRequest

#### Payload Schema

- **command** (string, required)
Connect message
- **version** (integer, required)
Protocol version
- **callId** (string, required)
Call unique identifier
- **applicationKey** (string, required)
Service unique identifier
- **codec** (string, required)
Audio codec used for encoding binary audio frames transmitted over the WebSocket connection.
Audio frames are 16-bit signed linear PCM, mono (single channel), with little-endian byte order.
- **sampleRate** (integer, required)
Audio sample rate in Hertz (Hz). The value is negotiated at call setup via the SVAML `connectStream` command.
Higher sample rates provide better audio quality but increase bandwidth and processing requirements.
- **8000 Hz**: Narrowband telephony quality (standard PSTN)
- **16000 Hz**: Wideband quality, suitable for most voice applications
- **24000 Hz**: High-quality voice
- **44100 Hz**: CD-quality audio
- **48000 Hz**: Professional audio standard
- **96000 Hz**: Ultra high-quality audio


For calls traversing the PSTN, audio is typically sampled at 8 kHz; using a higher value will not improve perceived quality.
Enum: 8000, 16000, 24000, 44100, 48000, 96000

- **callHeaders** (object, required)
Arbitrary key/value pairs (header name -> header value).