#!/usr/bin/env perl

use strict;
use warnings;

# Call this script with ./setpin.pl /dev/ttyUSB0 <yourpin>

my $modem = shift;
my $pin = shift;

$SIG{ALRM} = sub {
        die("timeout: no response from modem $modem\n");
};

open(MODEM, "+<", $modem) or die("can't open modem $modem");
alarm(10);
print(MODEM "AT+CPIN=\"$pin\"\n\r");
while (<MODEM>) {
        if (m/OK/) {
                close(MODEM);
                print("PIN accepted\n");
                exit(0);
        }
        if (m/ERROR/) {
                close(MODEM);
                print("PIN rejected\n");
                exit(1);
        }
}