Integration Manual

Table Of Contents
TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R26 System description
Page 68 of 162
Device including TOBY-L2
Cellular
Interface
SAP
Serial interface
(USB SAP channel)
Local SIM
(optional)
TOBY-L2
SAP client
Application
processor
Device including SIM
SAP
Serial interface
Remote SIM
Mobile
Equipment
SAP Server
Figure 30: Remote SIM access via completely wired connection
As stated in the SIM Access Profile Interoperability Specification [29], 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 TOBY-L2 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 31.
Device including TOBY-L2
SAP
Serial interface
(USB SAP channel)
Cellular
Interface
Local SIM
(optional)
TOBY-L2
SAP client
Application
processor
SAP
Bluetooth
interface
Bluetooth
Transceiver
Device including SIM
Remote SIM
Mobile
Equipment
SAP Server
Bluetooth
transceiver
Figure 31: Remote SIM access via Bluetooth and wired connection
The application processor can start an SAP connection negotiation between TOBY-L2 module SAP client and an
SAP server using a custom AT command (for more details see the u-blox AT Commands Manual [3]).
While the connection with the SAP server is not fully established, the TOBY-L2 module continues to operate with
the attached (local) SIM, if present. Once the connection is established and negotiated, the module performs a
detach operation from the local SIM followed by an attach operation to the remote one. Then the remotely
attached SIM is used for any cellular network operation.
URC indications are provided to inform the user about the state of both the local and remote SIM. The insertion
and the removal of the local SIM card are notified if a proper card presence detection circuit using the SIM_DET
pin of TOBY-L2 modules is implemented as shown in the section 2.5, and if the related “SIM card detection” and
“SIM hot insertion/removal” functions are enabled by AT commands (for more details see u-blox AT Commands
Manual [3], +UGPIOC, +UDCONF=50 AT commands).
Upon SAP deactivation, the TOBY-L2 modules perform a detach operation from the remote SIM followed by an
attach operation to the local one, if present.