> For the complete documentation index, see [llms.txt](https://learn.doubletick.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://learn.doubletick.io/voice-ai-agent/doubletick-telephony.md).

# DoubleTick Telephony

#### <mark style="color:$primary;">**What is DoubleTick Telephony?**</mark>

DoubleTick Telephony enables PSTN calling (regular phone calls) directly from the DoubleTick platform using channels provided by TATA.

Each call uses 2 channels — one connects to the agent's phone, the other connects to the end user. Both channels merge into a single conversation.

Call flow:

1. Agent initiates call from DoubleTick.
2. Channel 1 rings the agent's phone.
3. Agent picks up.
4. Channel 2 rings the end user.
5. Both channels merge.
6. Agent and end user speak.
7. Call ends, both channels are released.

PSTN numbers can also be onboarded on WhatsApp Cloud API. During onboarding, OTP must be triggered via call — SMS will not work on PSTN numbers.

#### <mark style="color:$primary;">Everything That Is Included</mark>

Once PSTN calling is enabled for a customer, here is what they get:

**Mobile Support** Click-to-Call works on mobile. Agents do not need to be on a desktop to make calls.

**CRM Integration** PSTN calling works inside Salesforce and other custom CRMs. Agents can make calls without leaving their CRM.

**Call Recordings** Every call is recorded. The recording is automatically saved inside the WhatsApp chat of that contact and is also visible in the Calls section of DoubleTick. (at additional cost of 0.02 per min deducted from the wallet)

**Transcription and Summary** Calls can be automatically transcribed and summarized. This is useful for managers who want to review calls without listening to the full recording.

**Call Analytics** Call metrics like talk time, number of calls, missed calls, etc., will be available inside Enterprise Analytics. This is currently being rolled out in the next 2 weeks.

**AI Calling** AI-powered calls work on PSTN as well. This means you can run automated AI calling campaigns through DoubleTick — not just WhatsApp.

**Call Routing** Inbound call routing is managed through the Inbound Call Trigger inside Bot Builder. Inbound call routing via Bot Builder is in the pipeline and not yet available.

**Multi-User Support** Multiple agents can be mapped to a single PSTN channel — just like how multiple agents work on a single WhatsApp number.

**Deactivation** A Deactivate button is available to turn off a PSTN channel. A Delete button is coming soon.

***

#### <mark style="color:$primary;">Documents Required from the Customer (TATA KYC)</mark>

Collect all of the following before starting the procurement process:

1. Incorporation Certificate or MSME Gumastha
2. GST Certificate
3. Company PAN Card
4. Signatory Person's ID Proof, Email ID, and Contact Number
5. Authorization Letter or BOR — required only if the company Director is not signing the documents
6. Company Address Proof
7. Aadhaar Card — for KYC verification

**Critical note on Aadhaar:** One Aadhaar card can be used to set up a maximum of 5 TATA channels. If you need more than 5 channels, you will need additional Aadhaar cards — one for every 5 channels.

***

#### <mark style="color:$primary;">**Understanding Channels and DID**</mark>

A **channel** is a single phone line that handles one call connection. Every call needs 2 channels (one per side).

A **DID number** (Direct Inward Dialing) is the actual phone number assigned to your channels — the number customers see on caller ID.

**How it works:**

* Client purchases channels from TATA.
* TATA deploys all channels on DoubleTick's AWS.
* Half the channels are onboarded on DoubleTick (agent side). The other half stay on DT's AWS (end user side).
* Example: 10 channels purchased → 5 onboarded on DT for agents, 5 on AWS for end user connections.

**Purchase rule:** TATA only sells in multiples of 10 (10, 20, 30...). You cannot buy 12, 15, 26, etc.

***

#### <mark style="color:$primary;">**Concurrency — How Many Channels Does a Client Need?**</mark>

Concurrency = number of agents on active calls at the same time.

**Formula:** Agents on calls simultaneously × 2 = Channels needed → round up to nearest multiple of 10.

| Agents on Calls | Channels Needed | Purchase (multiple of 10) |
| --------------- | --------------- | ------------------------- |
| 3               | 6               | 10                        |
| 5               | 10              | 10                        |
| 8               | 16              | 20                        |
| 15              | 30              | 30                        |
| 22              | 44              | 50                        |

This is based on **peak concurrency** — the max agents on calls at the same moment, not the total team size. 20 agents but only 5 on calls at once = 10 channels, not 40.

Not enough channels = calls will fail during peak hours. Too many = unnecessary fixed cost.

***

#### <mark style="color:$primary;">**Two Ways to Make PSTN Calls**</mark>

**1. Direct Calling from Chats** Agent calls a customer one-on-one from the Chats section. Channel 1 rings agent, Channel 2 rings customer, both merge. Billed at ₹0.60/min from DT wallet.

**2. PSTN Voice Campaigns** Bulk calling from a list. System dials automatically. PSTN cost (₹0.60/min) + AI cost (₹5/min) both apply.

|           | Direct Calling             | Voice Campaigns       |
| --------- | -------------------------- | --------------------- |
| Use case  | One-on-one calls           | Bulk outreach         |
| Who dials | Agent                      | System (automated)    |
| Billing   | ₹0.60/min (+ ₹5/min if AI) | ₹0.60/min + ₹5/min AI |


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