Dpl Port; Data/Fax Port; Sim Interface; Gpio Signals - Iridium 9523 Product Developer Manual

Iridium Communications, Inc.
Iridium 9523 Product Developer's Guide
Revision 7.0
The frame tick signal can have any mark:space ratio but must be externally synchronized to the Iridium
9523's internal clock. This is most easily achieved by double buffering the signal through two D-type
latches clocked by CODEC_PCMCLK.

3.4 DPL port

The DPL port is a three-wire asynchronous serial port. It carries 8-bit, no parity data at 115,200 baud.
The DPL port enables peripherals such as handsets and SIM card readers to be interfaced to the Iridium
9523. The interface utilizes an Iridium proprietary communication bus not detailed in this document.
Details can be made available after appropriate Non-Disclosure and/or License Agreements are
executed.
The serial data signals use standard 3.3V signals with conventional polarity. If desired, an external RS232
level converter could be fitted to the FA board to extend range.

3.5 Data/Fax port

The asynchronous serial data/fax interface is comprised of eight standard RS232 data (8-bit, no parity),
control, and status signals plus a ground level signal reference. This interface allows the FA to utilize the
Iridium 9523's modem functionality via AT command control. With respect to this interface, the Iridium
9523 behaves as a DCE (Data Communication Equipment), and the FA behaves as a DTE (Data
Terminal Equipment).
The data/fax interface supports 3.3V / LVTTL levels. If RS-232 voltage levels are needed, the FA must
include an LVTTL/RS-232 level shifter.
A 3-wire RS232 Data minimal interface may also be implemented; however the 9-wire interface offers
better control and is the recommended implementation.
Autobaud is enabled by default. Autobaud will occur on the following characters: 'a', 'A', or CR (carriage
return). Autobaud will also occur on the escape sequence character, provided this is an odd number
character. Normally this is set to '+' in register S2.
See the ISU AT Command Reference for further information on the data/fax interface.

3.6 SIM interface

The Iridium 9523 needs an external Iridium SIM card and socket to be connected to its SIM interface. The
signals operate at 3.3V logic levels, so an external SIM level converter such as the ONSemi NCN4555
must be connected between the Iridium 9523 and the SIM connector/socket to allow 3V or 1.8V SIM
cards to be used.
An external SIM card reader may also be interfaced as a peripheral to the Iridium 9523 via the DPL
interface. A SIM card in the external reader will take precedence over the SIM chip connected to the SIM
interface when both are present.

3.7 GPIO Signals

There are four GPIO signals to the Iridium 9523, as described in this section.
Iridium Communications, Inc.
Proprietary & Confidential Information
Only
Information Contained in this Guide
is Subject to Change Without Notice
Page 23 of 27
Distribution of Guide Restricted
to Product Developers