# Support
source: https://developer.mastercard.com/mastercard-merchant-presented-qr/documentation/device-sdks/support-sdks/index.md

## FAQs {#faqs}

Dynamically Allocable Tags are tags that can be used by any of the payment network operators with data objects that are context-specific and outside of the scope of EMVCo. The Dynamically Allocable Tag shall contain a primitive Globally Unique Identifier in Sub-Tag '00' to define the party that is using the tag. The Globally Unique Identifier can exist in one of the following three formats:

* An **Application Identifier (AID)** consisting of a RID registered with ISO and, optionally, a PIX, as defined by \[ISO 7816-4\]; for example 'A0000000041010' has been registered by Mastercard

* A **UUID** without the hyphen (-) separators, for example '581b314e257f41bfbbdc6384daa31d16'

* A **reverse domain name**, for example 'com.merchant.name'

Tag '26-51', Tag '80-99', Sub Tags '50-99' of Root-tag '62' are examples of Dynamically Allocable Tags in the EMVCo Specification.
The MAID is a unique ID assigned by Mastercard to specific merchant banks. This is used whenever the merchant bank has acquired a Mastercard QR merchant that is deemed to be eligible for the MAID criteria.

The MAID is denoted by the value contained in sub tag '01' immediately after the Mastercard AID of A0000000041010 with sub tag '00' encapsulated in any of the dynamically allocated tag between '26' to '51'. In the Bharat QR specifications in India, MAID may instead appear in tag '62' sub tag '11'.
The Receiving Institution will assign a unique 16-digit number from a specified Mastercard BIN range to each merchant Point of Sale (POS) terminal and will populate only the first 15 digits of the 16-digit Merchant ID in the Merchant ID field in the QR Code.

The Originating Institution will generate the 16th digit of the Merchant ID using the Luhn formula upon the consumer scanning the QR Code.

## Get Help {#get-help}

### Contact us for technical support. {#contact-us-for-technical-support}