TANGO55/i & TANGO56/i User's Manual
Version 1.05
The actual state of modems is displayed by two LED’s at the connector on the top of
interface C of the unit.
Green LED (GSM)
Off
Modem is off or run in SLEEP mode
600 ms On / 600 ms Off
No SIM card inserted or no PIN entered, or network search
in progress, or ongoing user authentication, or network
login in progress.
75 ms On / 3 s Off
Logged to network (monitoring control channels and user
interactions).
No call in progress.
75 ms On / 75 ms Off/
75 ms On / 3 ms Off
One or more GPRS contexts activated.
Flashing
Flashing Indicates GPRS data transfer: When a GPRS
transfer is in progress, the LED goes on within 1 second
after data packets were exchanged.
Flash duration is approximately 0.5 s.
On
On Depending on type of call:
Voice call:
Connected to remote party.
Data call:
Connected to remote party or exchange of
parameters while setting up or disconnecting a call.
Yellow LED
Off
Power off or interface C in use.
On
Power on, interface B in use or both interfaces (B & C) are
not connected.
4.2.1 Ignition line
The Ignition Line on Interface A uses an internal processor to control the timing of the
“TURN-ON” procedure of the internal GSM
module
.
The modem's power ON/OFF is controlled by the IGN sense line. When this line is
pulled high (10.8 to 31.2 Volt), the modem will power on. After the modem is
powered on, the IGN line can be pulled low. The modem will go sleep when this line
is pulled low and it receives AT+CFUN=n command via serial line, where
n=0,5,6,7,8,9. The modem will shut down when this line is pulled low and it receives
AT^SMSO command via serial line. See also AT Command description.
Following SLEEP modes are possible (when the modem is powered on):
When IGN state is Low,
SLEEP modes are applicable, but in error condition no
automatical reset will be performed.
When IGN state is High,
in error condition the modem resets automatically, but
SLEEP modes are not applicable.
4.2.2 Serial handling
The GSM/GPRS modem TANGO55/56 allows control of the GSM/GPRS modem over
the interface B or Interface C. The interface B is a implementation of a serial
interface corresponding to EIA-RS232-C.
See table below for details:
CCITT V24
Pin
Description
Direction
102
5
Signal Ground (GND)
103
3
Transmitted Data (TxD).
The DTE uses the TxD line to send data to the interface for
transmission over the Modem.
IN
104
2
Received Data (RxD).
The interface uses the RxD to send data received from the
Modem to the DTE.
OUT
105
7
Request To Send (RTS)
IN
106
8
Clear To Send (CTS)
OUT
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