### Answer Based on the available documentation, here are a few agent settings you can check that may impact call transfer/routing delays: 1. Ring Duration Setting The

ring_duration_ms

parameter controls how long the phone rings during call transfers. [(1) ]() - Default is 30,000 ms (30 seconds) - Valid range is [5000, 90000] ms - You can reduce this value to shorten wait times during transfers 2. Responsiveness Setting The

responsiveness

parameter controls how quickly the agent responds. - Value ranges from [0,1] - Higher values mean faster exchanges - Default is 1 3. STT Mode The

stt_mode

setting determines speech-to-text latency vs accuracy tradeoff. - Options:

fast

or

accurate

- Default is

fast

mode A similar delay issue was reported in a community discussion where a user experienced ~20 seconds of lag when forwarding calls from RingCentral to Retell—the agent would start talking from the beginning while the caller was still hearing ringing. [(2) ]() This was attributed to how the external phone system handles the forwarding path rather than Retell settings. Recommendations: - Check your practice phone system's forwarding configuration - Review the

ring_duration_ms

setting on your agent - Ensure

stt_mode

is set to

fast

if latency is the priority If the delay persists, the issue may be on the practice phone system side rather than Retell. For further troubleshooting, you can: - Visit [Contact Sales]() - Check [)

​ To learn more, see the sources I considered: [[1] Create Voice Agent](https://docs.retellai.com/api-references/create-agent) [[2] Discord message from @alex38853 on 2025-11-26](https://discord.com/channels/1186424376300679209/1294891368505937952/1443212998255837309) ​

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

@AI Evy where do I find SST settings

### Answer The

stt_mode

setting (speech-to-text mode) is configured at the Voice Agent level. [(1) ]() You can set or update it via the API when creating or updating an agent:

javascript
import Retell from 'retell-sdk';
const client = new Retell({
  apiKey: 'YOUR_RETELL_API_KEY',
}) ;
const agentResponse = await client.agent.create({
  response_engine: { llm_id: 'llm_234sdertfsdsfsdf', type: 'retell-llm' },
  voice_id: '11labs-Adrian',
}) ;

[(2) ]() The

stt_mode

parameter has two options: [(1) ]() -

fast

– prioritizes latency (default) -

accurate

– prioritizes transcription accuracy To update an existing agent's STT mode, use the [Update Voice Agent]() endpoint. If you're using the Retell Dashboard, look for the agent's configuration settings where you can adjust speech-to-text options. The API documentation doesn't specify the exact Dashboard location, so you may need to navigate to your agent's settings panel to find it there.

​ To learn more, see the sources I considered: [[1] Update Voice Agent](https://docs.retellai.com/api-references/update-agent) [[2] Create Voice Agent](https://docs.retellai.com/api-references/create-agent) ​

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

@AI Evy so the issue isn't a delay with the AI to caller, it's the caller to practice caller after the transfer

​ To learn more, see the sources I considered: [[1] Transfer call](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[2] Agent Transfer](https://docs.retellai.com/build/single-multi-prompt/transfer-agent) ​

### Answer ### Answer For delays occurring after the transfer (caller to practice phone system) , here are the Retell-side settings to check: Transfer Type Selection Consider using Warm Transfer instead of Cold Transfer. [(1) ]() - Cold transfer simply hands off the call to the destination number - Warm transfer provides more control, including human detection and connection timing Warm Transfer Settings That May Help - **Human detection**: When enabled, the agent checks if a human is present after the transfer target answers—the original caller is only connected once a human is detected - **Agent detection timeout**: The maximum time the AI waits to determine if the transfer target is human. Default is 30 seconds. Adjusting this may impact perceived delay - **Auto-greet**: If enabled, the agent immediately says "Hello" when the transfer target picks up, encouraging a faster response Alternative: Agent Transfer If you're transferring to another AI agent (not a human) , Agent Transfer offers significantly lower latency than call transfer—the transition is near-instant with no new phone call required [(2) ]() However, if the delay is happening on the practice phone system side (after Retell hands off the call) , that's likely outside Retell's control and would need to be addressed in your practice's phone system configuration.

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

### Answer I can see you've attached something, but I'm unable to view images or attachments directly. Based on the thread context about post-transfer delays (caller to practice phone system) , here are the key Retell warm transfer settings to review: Warm Transfer Configuration Options [(1) ]() [(2) ]() - **Agent detection timeout**: Maximum time the AI waits to determine if the transfer target is human. Default is 30 seconds—try adjusting this value [(1) ]() - **Human detection**: When enabled, the original caller is only connected once a human is detected on the receiving end - **Auto-greet**: If enabled, the agent immediately says "Hello" when the transfer target picks up, encouraging faster response and human detection - **On-hold music**: The audio played to the caller while on hold during transfer Caller ID Configuration [(1) ]() [(2) ]() You can configure which caller ID shows up to the transfer destination: - **Retell Agent's number**: Transfer destination sees the Retell agent's number - **User's Number**: Transfer destination sees the original caller's number (requires telephony provider support for caller ID override) If you can describe what the attachment shows or paste any error messages/logs, I can provide more targeted guidance. Alternatively, if the delay is occurring on the practice phone system side after Retell hands off the call, that would need to be addressed in your practice's phone system configuration.

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] Transfer call](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[2] Call Transfer Node](https://docs.retellai.com/build/conversation-flow/call-transfer-node) ​

@AI Evy So I was advising that the transfer is set to static destination the type is warm there is an extension with the DID and so they have to plug in or I'm sorry the AI plugs in the number display caller ID is set to user number, during transfer call is ringtone, during agent connection is transfer after detect human, everything else is off

### Answer Based on your configuration, the delay is likely coming from the human detection process during warm transfer. Here's what's happening and what you can adjust: Human Detection Timing When "transfer after detect human" is enabled, the AI waits to confirm a human has answered before connecting the original caller. [(1) ]() [(2) ]() This adds time to the transfer process. The Agent detection timeout setting controls how long the AI waits to determine if the transfer target is human—the default is 30 seconds. The caller remains on hold (hearing the ringtone you configured) until either: - A human is detected, or - The timeout is reached (marking the transfer as failed) Settings to Adjust 1. **Reduce Agent detection timeout**: Lower this from the default 30 seconds to something shorter if the practice typically answers quickly. 2. **Enable Auto-greet**: This makes the agent immediately say "Hello" when the transfer target picks up, encouraging a faster response and increasing the likelihood of detecting a human sooner. Caller ID Note You have "User's Number" selected for caller ID. Be aware that caller ID override requires telephony provider support. For warm transfers, Retell sets the

from

and

P-Asserted-Identity

SIP headers to the user's number—if your provider doesn't support this, the transfer could fail. If the delay persists after adjusting these settings, the issue may be on the practice phone system side (how quickly they answer or their IVR routing) .

​ To learn more, see the sources I considered: [[1] Transfer call](https://docs.retellai.com/build/single-multi-prompt/transfer-call) [[2] Call Transfer Node](https://docs.retellai.com/build/conversation-flow/call-transfer-node) ​

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

### Answer The Agent detection timeout setting is part of the warm transfer configuration. According to the documentation, it's found in the warm transfer settings section: [(1) ]() [(2) ]() Where to find it: When configuring a warm transfer (either in a Call Transfer Node or Transfer Call function) , the Agent detection timeout appears under the warm transfer-specific settings. The documentation describes it as: - "The maximum amount of time the AI agent will wait to determine whether the transfer target is a human. The caller is connected only if human detection succeeds within this timeframe. Otherwise, the transfer is marked as failed. The default timeout is 30 seconds." However, based on your description: If your setup is configured to transfer immediately when the receiving end picks up (without the AI speaking to the transfer target or waiting for human detection) , you may have human detection disabled. In that case, the agent detection timeout setting wouldn't apply—the call would connect as soon as the transfer target answers. If you're not seeing the timeout option, check whether "Enable human detection" is turned on in your warm transfer settings. The timeout setting only applies when human detection is enabled. If human detection is already off and you're still experiencing delays, the lag is likely occurring on the practice phone system side rather than within Retell's transfer process.

​ To learn more, see the sources I considered: [[1] Call Transfer Node](https://docs.retellai.com/build/conversation-flow/call-transfer-node) [[2] Transfer call](https://docs.retellai.com/build/single-multi-prompt/transfer-call) ​

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