Types & interfaces

Every interface and type below is exported from the package root (import { RtpConfig } from "t140llm") unless noted otherwise. Steganography types live in a separate module — see Steganography.

• Streams
• RtpConfig
• SrtpConfig
• TransportStream
• Processor options
• Metadata
• Errors
• WebSocket options

Streams

TextDataStream

type TextDataStream = EventEmitter | AsyncIterable<unknown>;

The input every processor accepts. An EventEmitter emits data, end, error, and optionally metadata events; an AsyncIterable yields chunks (the shape most LLM SDK streams return). Both are consumed directly — no wrapping.

RtpConfig

The configuration object shared by every RTP/SRTP transport. All fields are optional.

Field	Type	Meaning
payloadType	number	RTP payload type (default 96)
ssrc	number	Synchronization source (default: secure random)
initialSequenceNumber	number	Starting sequence number (default 0)
initialTimestamp	number	Starting timestamp (default 0)
timestampIncrement	number	Timestamp increment per packet (default 160)
fecEnabled	boolean	Enable Forward Error Correction (RFC 5109)
fecPayloadType	number	Payload type for FEC packets (default 97)
fecGroupSize	number	Media packets protected per FEC packet (default 3)
processBackspaces	boolean	Enable T.140 backspace processing
charRateLimit	number	Character rate limit (chars/sec)
redEnabled	boolean	Enable T.140 redundancy (RED)
redPayloadType	number	Payload type for RED encoding
redundancyLevel	number	Number of redundant T.140 blocks to include
customTransport	TransportStream	Use instead of the default UDP socket
handleMetadata	boolean	Detect and process LLM metadata
metadataCallback	(m: LLMMetadata) => void	Called for each metadata item
sendMetadataAsPackets	boolean	Send metadata as separate RTP packets
metadataPayloadType	number	Payload type for metadata packets
multiplexEnabled	boolean	Enable multiplexing multiple streams
streamIdentifier	string	Unique ID for this stream in a multiplex
csrcList	number[]	Contributing source identifiers
useCsrcForStreamId	boolean	Use the CSRC field for stream identification
markerBit	boolean	Set the RTP marker bit (RFC 4103 §5.1 M-bit, first packet after idle)
bomPrewarm	boolean	Send BOM (U+FEFF) on transport creation to open NAT pinholes (RFC 4103)

SrtpConfig

Extends RtpConfig (minus charRateLimit) with the SRTP key material.

Field	Type	Meaning
masterKey	Buffer	Required. SRTP master key
masterSalt	Buffer	Required. SRTP master salt
profile	SrtpProtectionProfile	Crypto profile (default profile 1)
isSRTCP	boolean	Treat as SRTCP (default false)

SrtpProtectionProfile

Valid values per the IANA SRTP registry:

Value	Profile
0x0001	SRTP_AES128_CM_HMAC_SHA1_80
0x0002	SRTP_AES128_CM_HMAC_SHA1_32
0x0005	SRTP_AEAD_AES_128_GCM
0x0006	SRTP_AEAD_AES_256_GCM
0x0007	DOUBLE_AEAD_AES_128_GCM_AEAD_AES_128_GCM
0x0008	DOUBLE_AEAD_AES_256_GCM_AEAD_AES_256_GCM

TransportStream

Implement this to plug in a custom transport (WebRTC data channel, steganographic carrier, etc.). Pass it as RtpConfig.customTransport.

interface TransportStream {
  send(data: Buffer, callback?: (error?: Error) => void): void;
  close?(): void;
}

Processor options

Passed as the third argument to processAIStream and to attachStream on pre-created transports.

interface ProcessorOptions {
  processBackspaces?: boolean;
  handleMetadata?: boolean;
  metadataCallback?: (metadata: LLMMetadata) => void;
  sendMetadataOverTransport?: boolean;
  onError?: (error: Error) => void;
  preCreateConnection?: boolean;
}

AttachStreamOptions extends this with sendMetadataOverWebsocket?: boolean and tlsOptions?: TLSOptions.

Metadata

interface LLMMetadata {
  type: 'tool_call' | 'tool_result' | 'custom' | 'reasoning' | string;
  content: unknown;
  id?: string;
}

Emitted for tool calls, tool results, reasoning, and custom provider metadata. Enable with handleMetadata: true and receive via metadataCallback. See reasoning streams.

Errors

T140RtpTransport emits typed errors on its error event.

interface T140RtpError {
  type: T140RtpErrorType;
  message: string;
  cause?: Error;
}

T140RtpErrorType is an enum:

Value	When
NETWORK_ERROR	UDP socket / network failures
ENCRYPTION_ERROR	SRTP encryption failures
FEC_ERROR	FEC packet creation failures
INVALID_CONFIG	Invalid or missing configuration
RATE_LIMIT_ERROR	Rate-limit handling failures
RESOURCE_ERROR	Socket allocation/deallocation failures

import { T140RtpErrorType } from "t140llm";

transport.on("error", (err) => {
  if (err.type === T140RtpErrorType.NETWORK_ERROR) { /* ... */ }
});

WebSocket options

interface TLSOptions {
  rejectUnauthorized?: boolean;
  ca?: string;
  cert?: string;
  key?: string;
}

interface WebSocketOptions {
  tlsOptions?: TLSOptions;
}