Pin mapping from modem(26pin) to 25 pin Sub-D:

^source^dst^signal^
|1,2,3| -> 4,16|EXT_PWR|
|4,5,6| -> 3,17|EXT_GND|
|7| -> 1|ON/OFF|
|10,13,20,23| -> 14,23,25|SIG_GND|
|11| -> 9|S_TX (Serial Data into SBD)|
|12| -> 13|S_RX (Serial Data out)|
|14| -> 10|DCD|
|15| -> 21|DSR|
|16| -> 22|CTS|
|17| -> 7|RI|
|18| -> 8|RTS|
|19| -> 19|DTR|
|24| -> 24|network_available|
|8,9,21,22,25,26 n.c.|||