Black Box MD1650A-JP, Reference Manual

Page: 33 / 56

CHAPTER 2: AT Commands
31
Operation in Data Mode: Line-In-Use (Enabled by AT-STE=1, AT-STE=3, AT-STE=5, or
AT-STE=7)
Case 1: Telephone Line is in Use
If an ATDT, ATDP, or ATDL is issued while Line-In-Use detection is
enabled and the telephone line is in use, the modem will immediately
return the message LINE-IN-USE to the DTE without going off-hook,
then return to command mode.
Case 2: Telephone Line is in Use But Disconnected
If an ATDT, ATDP, or ATDL is issued while Line-In-Use detection is
enabled and the telephone line is NOT in use, the modem will go off-
hook after a short pause, then respond with CONNECT or NO
CARRIER message.
Case 3: Telephone Line is Not Connected to Modem
If an ATDT, ATDP, or ATDL is issued while Line-In-Use detection is
enabled and the telephone line is not connected, the modem will go
off-hook momentarily, go back on-hook, then respond with NO DIAL
TONE message.
Extension Pick-up (Enabled by AT-STE=2, AT-STE=3, AT-STE=6, or
AT-STE=7):
Case 1: Modem Off-Hook, Local Handset Goes Off-Hook
If the local handset goes off-hook while the modem is in a data
connection, the modem will then send a GSTN Clear down to the
remote modem and then go on-hook. The modem will then send a NO
CARRIER message to the DTE. A result code of 25 will be left in S86
register.
Remote Hang-up (enabled by AT-STE=4, AT-STE=5, AT-STE=6, or AT-
STE=7):
Case 1: Modem Off-Hook, Remote Hang-Up
If the modem is connected (off-hook) and the remote modem/server
hangs up, the central office may issue a line polarity reversal. If a line
polarity reversal is detected, the modem will drop the call and respond
with NO CARRIER. The reason for hang-up can be determined by #UD
or by S86=25. A line reversal can also be simulated by simply pulling
out the telephone line during a connection.
Operation in Voice Mode: Line-In-Use (enabled by AT-STE=1, AT-STE=3, AT-STE=5, or
AT-STE=7):
This feature does not apply in voice mode.
Extension Pickup (Enabled by AT-STE=2, AT-STE=3, AT-STE=6, or
AT-STE=7)
If the modem is off-hook and an extension goes off-hook, the modem
issues a <DLE>P to the DTE. The application software then hangs up
the line (VLS=0).
Remote Hang-up (Enabled by AT-STE=4, AT-STE=5, AT-STE=6, or
AT-STE=7).
If the modem is off-hook and the remote user goes on-hook, the
modem issues a <DLE>P to the DTE. The application software then
hangs up the line (VLS=0).