Table of Contents
Advertisement
Iridium Communications, Inc.
Iridium 9523 Product Developers' Guide
Revision 2.6
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).
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 AT Command Reference for details.
3.5.1
9-Wire and 3-Wire Operation
By default, the serial interface operates as a 9-wire connection. Table 11 describes each of the signals,
where "input" means an input to the Iridium 9523, and vice-versa for "output".
Signal
RX
Active high data output [The FA receives the data from the Iridium 9523]
TX
Active high data input [Data is transmitted from the FA to the Iridium 9523]
GND
0V
RTS
Active low flow control input
Active low flow control output
CTS
RTS and CTS are used together to implement hardware flow control when enabled with
AT&K3, refer to section 5.7.13
Active low handshaking input
DTR
AT&Dn controls how the Iridium 9523 uses DTR, refer to section 5.7.11
Active low handshaking output
The Iridium 9523 drives DSR ON
DSR
The FA may use this signal as an indication that the Iridium 9523 is powered up and
ready to receive AT commands
Iridium Communications, Inc.
Proprietary & Confidential Information
Only
Table 11: Data/Fax Port Serial Interface Signals
Description
Page 26 of 115
Information Contained in this Guide
is Subject to Change Without Notice
Distribution of Guide Restricted
to Product Developers
Advertisement
Table of Contents
