From the METAL language reference files:

MODEM(1)=0    Resets the modem using the init string in the METAL.CONFIG
file
MODEM(1)=1    Hangs up the modem
MODEM(1)=2    Set modem to auto-answer
MODEM(1)=3    Takes modem off-hook and generates a carrier (manual answer)
MODEM(1)=4    Takes the modem off-hook

x=MODEM(1)
x=0 thru 4            Last modem command executed
x=5                    Modem is now online.    y=MODEM(2), y is the baud
rate of the connection
x=6                    Modem has "lost carrier"


MODEM$=i$    Sends contents of i$ to the modem

Basically, to take the modem off hook and send data...do something like
this:

MODEM(1)=0                            <-- Reset the modem
MODEM(1)=4                            <--take modem off-hook
MODEM$="ATDT5551212"      <--Dial the number
do
 x=MODEM(1)                            <--wait for a carrier
until x=5
MODEM$="data to send"
for x=1 to 100:next                        <--give data time to be
transmitted
MODEM(1)=1                              <--Hang up the modem
MODEM(1)=0                            <-- Reset the modem
MODEM(1)=2                            <--go back to waiting for a call...