Comtrol AT Commands - Manual (Page 78)

AT Commands for CX81801/CX06833/CX81300/CX06827 Modems Reference Manual
Conexant 102184B
3-52
Case 2: Modem off-hook, Extension Pick-up
If the modem is connected and another extension goes off-hook, the modem will send a
GSTN Cleardown to the remote modem and then immediately hang-up. Due to the noise
possibly being added to the line when a telephone extension is picked-up, a GSTN
Cleardown may or may not successfully be received by the remote mode. If the GSTN
Cleardown is not received successfully by the remote modem, the remote modem may
attempt a retrain until the retrain fails and the remote modem drops the line. In any case,
the modem will send an OFF HOOK INTRUSION message to the DTE immediately
after sending the GSTN Cleardown. A result code of 25 will be left in the S86 register.
Because the extension is off-hook, the modem cannot flash the hook for the central office
to generate a dial tone. In this case, the user must flash the extension handset to obtain a
dial tone.
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 goes 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 LINE REVERSAL DETECTED. 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 should then hang 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 should then hang up the line (VLS=0).
Examples
User is talking on an extension and the modem tries to dial
AT-STE=7
ATDT555-1212
LINE IN USE