Abstract: The claimed subject matter can provide an architecture that interfaces a single slave device such as a UICC smartcard with multiple host controllers. For example, a secondary host can be interfaced between a primary host (e.g. a controller in a cellular phone, a PDA, an MP3 player . . . ) to manage all transactions with the slave device. The secondary host can operate transparently to the primary host and thus does not require any modifications to the primary host. This can be accomplished, e.g. by employing the CMD channel (which is relatively sparsely used by the primary host) to communicate both commands and data with the slave. Moreover, the transactions initiated by the secondary host can be segmented into many smaller fragments and interleaved between transactions initiated by the primary host. In addition, the secondary host can temporarily take on the role of the slave device and affect direct communication with the primary host.