Module bridge 

Vendor-neutral call-bridge components.

Every contact-center connector — Twilio Media Streams, a raw SIP/RTP leg, a platform’s gRPC virtual-agent slot — reduces to the same duties: move audio frames both ways through voice::pump, land caller keypresses and call identity in session state where flow guards read them, and keep the caller’s ear busy while slow work runs. This module holds those duties as small, connector-agnostic components, so a new connector composes them instead of re-inventing them.

Nothing here owns a socket. Connectors own transport; these components own semantics.

Structs

DtmfDeduper

Deduplicates RFC 4733 end-of-event packets.

FillerConfig

Configuration for spawn_latency_filler.

KeypadGuard

Keeps keypad tones and masked keypad entry away from the model.

Constants

KEY_CALLER

State key holding the caller identity the transport presented (SIP From, a platform’s ANI field, …).

KEY_CALL_SID

State key holding the transport’s call identifier once known.

KEY_DTMF

State key holding the most recent DTMF digit pressed by the caller.

KEY_DTMF_HISTORY

State key holding every DTMF digit pressed so far, concatenated in order.

KEY_KEYPAD_DONE

Set to true when the caller presses # while the keypad is masked.

KEY_KEYPAD_ENTRY

Digits keyed while the keypad was masked, in order. The key is marked sensitive (State::redact_keys): tools read the real value, while journals, exports and telemetry see it redacted.

KEY_KEYPAD_LEN

How many digits KEY_KEYPAD_ENTRY holds. Not sensitive, so a flow can guard on it.

KEY_KEYPAD_MASK

Set this state key to true to mask the keypad: while it is set, the caller’s audio reaches neither the model nor the recording (it is replaced with silence), and keypresses go to KEY_KEYPAD_ENTRY instead of KEY_DTMF. This is the “pause and resume” pattern for taking card numbers and PINs by keypad. Set it back to false to resume.

KEY_STREAM_SID

State key holding the transport’s media-stream identifier once known.

Functions

keypad_masked

Whether the keypad is masked (see KEY_KEYPAD_MASK).

record_dtmf

Record one DTMF keypress into session state under the shared keys.

spawn_latency_filler

Keep the caller’s ear busy while the model is slow: when the caller stops speaking (LiveEvent::VadEnd) and no model audio arrives within config.delay, inject the configured clip into the connector’s playback channel. Model audio or an interruption disarms the timer; a Playback::Flush from a barge-in clears any queued filler exactly like any other queued audio.