Historically MDCs were used for repair related purposes by landline and wireless carriers.
Businesses can send automatic responses upon contact, such as by text message.
Inbound calls to MDCs can either be automatically routed based upon the area code of the caller, or by asking the caller to type out speak their zip code into the phone.
Abbreviated dialing codes[2] involve a similar technology that supports only voice calls.
A 2D bar code[3] involves the use of a graphic that must be photographed or scanned by a mobile phone camera prior to presenting the caller with a response.