SARA-G3 and SARA-U2 series - System Integration Manual 
UBX-13000995 - R26    System description 
    Page 95 of 217 
1.13.22  SIM Access Profile (SAP) 
  Not supported by SARA-G3 modules. 
 
SIM access profile (SAP) feature allows SARA-U2 modules to access and use a remote (U)SIM card instead of the 
local SIM card directly connected to the module (U)SIM interface. 
SARA-U2 modules provide a dedicated USB SAP channel and dedicated multiplexer SAP channel over UART for 
communication with the remote (U)SIM card. 
The communication between SARA-U2 modules and the remote SIM is conformed to client-server paradigm: the 
SARA-U2 module is  the SAP client  establishing a connection  and performing data  exchange to  an  SAP server 
directly connected to the remote SIM that is used by SARA-U2 module for GSM/UMTS network operations. The 
SAP communication protocol is based on the SIM Access Profile Interoperability Specification [30]. 
 
  SARA-U2 modules do not support SAP server role: the module acts as SAP client only. 
 
A typical application using the SAP feature is the scenario where a device such as an embedded car-phone with 
an integrated SARA-U2 module uses a remote SIM included in an external user device (e.g. a simple SIM card 
reader  or  a  portable  phone),  which  is  brought  into  the  car.  The  car-phone  accesses  the  GSM/UMTS  network 
using the remote SIM in the external device. 
SARA-U2  modules,  acting  as  an  SAP  client,  can  be  connected  to  an  SAP  server  by  a  completely  wired 
connection, as shown in Figure 38. 
 
Device including SARA-U2 
GSM/UMTS 
interface
SAP             
Serial interface
(SAP channel over 
USB or UART)
Local SIM
(optional)
SARA-U2
SAP client
Application
processor
Device including SIM
SAP                   
Serial interface
Remote SIM
Mobile
Equipment
SAP Server
 
Figure 38: Remote SIM access via completely wired connection 
As stated in the SIM Access Profile Interoperability Specification [30], the SAP client can be connected to the SAP 
server by means of a Bluetooth wireless link, using additional Bluetooth transceivers. In this case, the application 
processor wired to SARA-U2 modules establishes and controls the Bluetooth connection using the SAP profile, 
and routes data received over a serial interface channel to data transferred over a Bluetooth interface and vice 
versa, as shown in Figure 39.