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Chapter 3 - AT Commands
$Tn Calling Tone
n = 0 or 1
Default: $T1
The $T command enables or disables the modem’s calling tone, which is required by some
European countries to identify the caller as a modem.
$T0 enables the calling tone.
$T1 disables the calling tone.
#Tn Trellis-Coded Modulation
n = 0 or 1
Default: #T1
The #T command enables or disables trellis-coded modulation (TCM) on the modem. There
is usually no need to disable TCM, except for an unusual line condition called impulse
noise.
#T0 disables TCM.
#T1 enables TCM.
Yn Long Space Disconnect
n = 0 or 1
Default: Y0
When two modems are connected in reliable mode, a link disconnect request packet is sent
to request a disconnect. In non-error correction mode, there is no “polite” way to request a
disconnect. As a result, some “garbage” may be received when a hang-up command is
issued.
Y0 disables the modem’s use of the break signal.
Y1 enables the modem’s use of the break signal, which shuts off the modem’s receiver and
disconnects (both modems must have Y1 enabled).