I am using an ARM920T machine with Samsumg SMDK 2410 and a Linux embedded and a 2.4.18 kernel , BusyBox 0.60.3

I want to use a modem
I connect my external modem ( Falcom A2D ) to the ttyS1
but when I do
cat < /dev/ttyS1 &
cat > /dev/ttyS1
AT

the modem don't reply


the command setserial /dev/ttyS1 -a says

/dev/ttyS1 , Line 1,UART undefined,Port: 0x50004000, IRQ: 55
Baud_base: 3125000, close_delay: 50, divisor: 0
Flags: spd_normal


UART is the s3c2410 , the IRQ and port number seems to be correct


what I have to do ?

any help will be appreciated

thanks