9-Wire And 3-Wire Operation - Iridium 9601 Product Developer Manual

Iridium Satellite LLC
9601 SBD Transceiver Product Developers Guide
V1.24 120505

3.3.1 9-Wire and 3-Wire Operation

By default, the serial interface operates as a 9-wire connection. Table 9 describes each of the signals,
w h e r e " i n p u t " me a n s a n i n p u t t o t h e 9601, a n d " o u t p u t " me a n s a n o u t p u t f r o m t h e 9601 SBD Transceiver.
Signal
RX Active high data input
TX Active high data output
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
Active low handshaking input
AT&Dn controls how the 9601 uses DTR:
 If set to AT&D0, DTR is always ignored.
 Otherwise DTR set to OFF places the data port into UART test mode after 10
DTR
seconds, or immediately on boot-up. A subsequent transition of DTR to ON returns
the data port to DCE mode and resets it to its power-on state.
 The UART test mode is provided for factory testing of the data port UART. An FA
should never activate test mode; if it does, the 9601 will stop responding to AT
commands until the data port is returned to DCE mode.
Active low handshaking output
The 9601 drives DSR ON when the data port is in DCE mode, and OFF when the data
DSR port is in test mode.
The DTE may use this signal as an indication that the 9601 is powered up and ready to
receive AT commands.
Active low ring indicator output
RI
The 9601 drives RI ON when it receives a Automatic Notification from the network that a
Mobile Terminated SBD Message is queued at the Gateway, and drives RI OFF after 5
seconds or when the DTE initiates an SBD session, whichever occurs first.
Active low handshaking output
DCD
DCD is driven OFF at all times.
Note that the Ring Indicator (RI) pin is used by the 9601 SBD Transceiver to indicate that a Mobile
Terminated SBD (MT-SBD) message is queued at the Gateway. The Field Application will need to
monitor this pin and use appropriate AT Commands to command the Transceiver to retrieve the MT-SBD
message.
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Table 9 –Serial Interface Signals
Description
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