# Non-eCommerce Integrations
source: https://developer.mastercard.com/mastercard-gateway/documentation/integrations-types/hosted-checkout/integrate-gateway-features/non-ecommerce-integrations/index.md

You can use the Hosted Checkout with any transaction source configured on your merchant profile (such as Internet, call center, or telephone order). To define the transaction source, include the `transaction.source` field in the INITIATE CHECKOUT request.

For the `transaction.source` field:

* If the value is something other than INTERNET, payment methods that require the payer to be present are not supported.
* Is not included in the request, it defaults to INTERNET, if supported on your merchant-acquirer link. If not supported, it defaults to the transaction source in your merchant profile.

## Controlling the Card Security Code Field {#controlling-the-card-security-code-field}

You can control whether payers are required to provide the Card Security Code to process the payment by setting `interaction.displayControl.cardSecurityCode` in the INITIATE CHECKOUT request to one of the following values.

* OPTIONAL: If you want the Hosted Payment Page to display the Card Security Code input field, but input to this field is not mandatory.
* MANDATORY (default): If you want the Hosted Payment Page to display the Card Security Code input field and make it mandatory.

Warning: Be careful about making the Card Security Code optional, as some acquirers require it to process the transaction.