= GW16130 Iridium Satellite Modem =
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GW16130 = GW16127 Mini-PCIe carrier + Iridium 9603 modem module

Iridium 9602/9603 SBD (short burst data) modem is capable of transmitting ASCII or Binary messages in packets of up to 340 bytes, and receiving packets of up to 270 bytes.

== Modem Activation ==

Modems need to be activated via an approved Iridium carrier / provider. 

During the activation, the modem is configured for the destination of the messages:
 * Direct IP
 * Email address
 * Another modem

Some providers found on the internet, but not endorsed or approved by Gateworks:
 * https://www.northernaxcess.com/sbd-short-burst-data-airtime-plans
 * https://satellitephonestore.com/iridium-sdb
 * https://www.satphonestore.com/airtime/iridium-sbd.html
 * http://www.rock7mobile.com/products-rockblock-9603
 * http://www.nalresearch.com/Airtime.html#Short%20Burst%20Data%20(Standard%20Plan)



== FTDI GPIO Control ==

An FTDI FT231XQ USB UART Chip is used to communicate with the Iridium Satcom modem via its UART.

The FTDI GPIO pins control the modem:

CBUS0: SAT_ON (input to modem; 10k pull-down)
CBUS1: SAT_FND (output from modem)
CBUS2: SAT_SUPPLY_OUT (output from modem)
CBUS3: not connected

Configure GPIO:
{{{
base=$(for i in $(ls -1d /sys/class/gpio/gpiochip*); do [ "ftdi-cbus" = "$(cat $i/label)" ] && cat $i/base; done)
[ "$base" ] || { echo "Error: could not find ftdi-cbus device"; }
echo $((base+0)) > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio$((base+0))/direction
echo 1 > /sys/class/gpio/gpio$((base+0))/value # enable modem
echo $((base+1)) > /sys/class/gpio/export
echo in > /sys/class/gpio/gpio$((base+1))/direction
echo $((base+2)) > /sys/class/gpio/export
echo in > /sys/class/gpio/gpio$((base+2))/direction
}}}