Abstract: A programmable data port interface adapter for a mobile data terminal is disclosed which provides selectable configuration of an external device data port connector for accommodating multiple types of data port devices. An RS-232 type data port may be configured to a J1708 type data port such that the mobile data terminal may communicate with RS-232 type devices in addition to J1708 type devices. Data port configuration and control is implemented by software thereby eliminating the need to upgrade of modify data port hardware to accommodate multiple data port type devices. Multiple data port connectors may be utilized in a multiple programmable combinations and configurations. Configuration information may be received by the mobile data terminal or through remote communications such as an RF or cellular network.