Iridium Communications Inc.
Information Contained in this Guide
9602 SBD Transceiver Product Developers Guide is Subject to Change Without Notice
Revision 4.0
Iridium Communications Inc.
Distribution of Guide Restricted
Proprietary & Confidential Information 20 to Product Developers Only
3.2.4 Power On/Off Control
An external on/off input is provided on a pin of the User connector. The 9602 starts up when power is
applied and the power on/off input is high. As long as the input voltage is applied, logic high on this line
turns the transceiver on and a logic low turns it off. If this line is not required then it must be connected
directly to the +5 V supply.
Note that this on/off control is similar to the 9601 product but it is
not
the same as the 9522, 9522A or
9522B products.
Prior to turning off the modem a “flush memory” (AT*F) command should be issued to ensure all memory
write activity is completed. When a transceiver has been turned off, Product Developers should not
reapply power on a unit until more than 2 seconds has elapsed after power has reached 0V. Additionally,
if a unit does not respond to AT commands, power off the module, wait for 2 seconds and then power it
back on.
When a 9602 is powered off the power on reset circuit requires 2 seconds for voltages to decay. If the 2
second wait time is not adhered to the reset circuit may not operate and the modem could be placed in a
non-operational state. The state is not permanent and can be rectified by the above procedure.
3.2.5 Typical Power Usage Profile
This section is designed to give the Product Developer some insight to the electrical power profile that the
9602 uses. It does not describe every situation and permutation possible. It should be used as a starting
point for the Product Developer to continue its own development design. The actual usage profile can
vary for a number of reasons:
1) View of the sky – if in poor visibility of the sky where a clear line of sight is not available between
the transceiver and the satellite.
2) The higher the antenna VSWR the higher the current consumed
3) How often the 9602 module is activated/deactivated by the Host Controller system
4) Manufacturing variation from transceiver to transceiver.
The host system designer should ensure their design covers for worst case power consumption
scenarios. Figure 6 provides a graphical representation of the typical supply current profile of a 9602 SBD
Transceiver sending and receiving SBD messages.
