# 2-way SMS communication

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If you plan on using a **US long number**, please refer to the [10DLC section](https://guides.clickatell.com/sms-channel/10dlc-regulations-us/what-is-10dlc) of this guide.
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**2-way** SMS communication involves **sending and receiving** messages, i.e., customers can reply to the messages sent by your business.

To engage in 2-way SMS communication, you require a **dedicated number.** 

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Only relevant to self-serve clients. For other packages, Clickatell does this on your behalf.
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* You can purchase a[ long number](https://guides.clickatell.com/sms-channel/long-numbers) or a [short code](https://guides.clickatell.com/sms-channel/short-codes) from *My Workspace -> SMS* and link it to the 2-way SMS integration. 
* Numbers can also be purchased as part of the [2-way SMS setup wizard](https://guides.clickatell.com/sms-channel/getting-started/add-new-sms-setups-self-serve).

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Learn how to send 2-way messages using [One API](https://docs.clickatell.com/channels/one-api/one-api-reference/#tag/One-API/operation/sendMessageREST).
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