​ To learn more, see the sources I considered: [[1] Connect to web call](https://docs.retellai.com/deploy/web-call) [[2] Issues with Portuguese (PT-PT) Voice Agent: Latency, Audio Recognition, and Email Capture](https://community.retellai.com/t/issues-with-portuguese-pt-pt-voice-agent-latency-audio-recognition-and-email-capture/711) [[3] Persistent issue - gpt-realtime doesn't detect short phrases like "yes"](https://community.retellai.com/t/persistent-issue-gpt-realtime-doesnt-detect-short-phrases-like-yes/177) [[4] ASR errors](https://discord.com/channels/1186424376300679209/1217142861737492510) [[5] Italian Voice Agent Sometimes Fails to Progress Despite Clear Audio](https://discord.com/channels/1186424376300679209/1420472399270383730) ​

### Answer Based on the available sources, there are several troubleshooting steps for web call audio issues: Check your audio device configuration: When starting a web call, you can specify the microphone device using the

captureDeviceId

parameter [(1) ]() :

javascript
await retellWebClient.startCall({
 accessToken: createCallResponse.access_token,
 sampleRate: 24000,
 captureDeviceId: "default",
 playbackDeviceId:
 "0ec1807fd0fe6e51b990660ec4e2ebb78sdfcba51e279815d00c423ce03407ff",
 emitRawAudioSamples: false,
}) ;

Listen to call events for debugging: Monitor the

call_started

,

call_ended

, and

error

events to identify issues :

javascript
retellWebClient.on("call_started", () => {
 console.log("call started") ;
}) ;

retellWebClient.on("error", (error) => {
 console.error("An error occurred:", error) ;
 retellWebClient.stopCall() ;
}) ;

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

Known ASR issues: Other users have reported similar audio recognition problems [(2) ]() [(3) ]() [(4) ]() [(5) ]() . The team has acknowledged working on improvements for speech recognition, particularly for short phrases and certain languages [(4) ]() [(5) ]() . If the issue persists, check your browser permissions for microphone access and verify your access token is valid (tokens expire after 30 seconds if the call isn't started) [(1) ]() .

### Answer Yes, you can schedule a single call using Retell AI's batch calling feature [(1) ]() [(2) ]() . When creating a batch call, you can include just one task in the

tasks

array [(2) ]() . You can then choose to either "Send Now" to start the call immediately or "Schedule" for a future time [(1) ]() . Here's how the API structure works for a single scheduled call [(2) ]() :

javascript
import Retell from 'retell-sdk';
const client = new Retell({
 apiKey: 'YOUR_RETELL_API_KEY',
}) ;
const batchCallResponse = await client.batchCall.createBatchCall({
 from_number: '+14157774444',
 tasks: [{ to_number: '+12137774445' }],
}) ;
console.log(batchCallResponse.batch_call_id) ;

To schedule it for a specific time, you would include the

trigger_timestamp

parameter, which represents the scheduled time as a Unix timestamp in milliseconds . If you omit this parameter, the call will be sent immediately .

​ To learn more, see the sources I considered: [[1] Create Batch calls](https://docs.retellai.com/deploy/make-batch-call) [[2] Create Batch Call](https://docs.retellai.com/api-references/create-batch-call) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

​ To learn more, see the sources I considered: [[1] Create Batch Call](https://docs.retellai.com/api-references/create-batch-call) [[2] Create Batch calls](https://docs.retellai.com/deploy/make-batch-call) ​

### Answer Yes, batch calling can work with just one phone number [(1) ]() [(2) ]() . While batch calling is designed to handle multiple calls efficiently, the

tasks

array in the API accepts any number of tasks—including just one [(1) ]() . Each task represents a single outbound call , so you can create a batch call with a single task if you only need to schedule one call [(2) ]() . The batch call feature is flexible for both single and bulk scenarios .

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Based on the available sources, batch calling does not automatically handle dynamic rescheduling during a call [(1) ]() [(2) ]() . Batch calls are created with a predefined schedule using the

trigger_timestamp

parameter when you create the batch call [(2) ]() . The scheduled time is set as a Unix timestamp in milliseconds . Once a batch call is scheduled, it executes at that predetermined time [(1) ]() [(2) ]() . If during a call the person requests a different time, you would need to: 1. Capture that requested time during the conversation (your AI agent would need to be configured to handle this) 2. Create a new batch call with the rescheduled time using the API The batch calling feature itself doesn't have built-in logic to dynamically reschedule based on in-call requests . You'd need to implement custom logic in your agent to: - Detect the reschedule request - Collect the new preferred time - Trigger a new batch call creation via the API with the updated

trigger_timestamp

[(2) ]() This would require integration with your backend systems to programmatically create new scheduled batch calls based on the conversation outcome.

​ To learn more, see the sources I considered: [[1] Create Batch calls](https://docs.retellai.com/deploy/make-batch-call) [[2] Create Batch Call](https://docs.retellai.com/api-references/create-batch-call) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer --- Retell AI supports scheduled calling through its Batch Call feature [(1) ]() [(2) ]() . When creating a batch call, you can schedule it for a future time using the

trigger_timestamp

parameter, which accepts a Unix timestamp in milliseconds [(1) ]() . If you omit this parameter, the call will be sent immediately . You can create batch calls with just one task (single call) or multiple tasks [(1) ]() [(2) ]() . When creating a batch call via the dashboard, you have two options: "Send Now" to start calls immediately or "Schedule" for a future time [(2) ]() . The scheduling functionality allows you to define specific time windows for when calls should be made . While I don't have information about Vapi's specific implementation to compare directly, Retell's batch calling feature does provide scheduling capabilities for outbound calls through the

trigger_timestamp

parameter [(1) ]() .

​ To learn more, see the sources I considered: [[1] Create Batch Call](https://docs.retellai.com/api-references/create-batch-call) [[2] Create Batch calls](https://docs.retellai.com/deploy/make-batch-call) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.