An enhanced "Camel-back" or "Companion" Digital Organizer (CDO) is described that is designed to interface to a cellular telephone. The CDO is preferably implemented as an add-on component which can be easily attached and detached from a phone by a user and, once in place, can dramatically enhance the phone's functionality by converting the phone into a "smart" phone. Exemplary features of the CDO include an ability for the user to initiate a voice call on the phone from the CDO. Preferably, the user may initiate the voice call from any of multiple modules of the user's data, and not merely from a phone-book module. The CDO is also capable of stand-alone use as a personal organizer device, apart from the phone. The CDO preferably includes a docking unit that removably mates to particular model(s) of phones, and a main unit that removably docks to the docking unit. The docking unit preferably includes substantially all phone-model-specific geometries and features to thereby allow the main unit to be configured for stand-alone use as an organizer with few compromises made to accommodate specific model(s) of phones. Furthermore, the same main unit is suitable for use with multiple docking units that are respectively adapted for different models of phones. Note that some phones have an "automatic hang-up" feature in which the phone unilaterally hangs up a phone call that was initiated by an external device (e.g., a modem or the CDO) upon detaching of the device by the user. For such phones, the docking unit remains attached to the phone during a call initiated by the user via the CDO, even if the user should detach the main unit for stand-alone use as an organizer. The still-attached docking unit contains sufficient circuitry and physical features to prevent automatic hang-up. The main unit includes many features such as a choice of both left- and right-handed modes and the capability for handling electronic mail, remote browsing, remote synchronization, caller identification, and the like.