A N 9 3
250
Rev. 1.4
If
there
is
no
response
from
the
receive
modem,
the
transmit
modem
will
time
out,
go
on
hook
and
report
NO
CARRIER
to
the
host.
The
transmitter
can't
resend
the
data
before
the
time
out
has
expired,
because
this
will
cause
a
character
abort.
This
scenario
can
be
avoided
by
including
the
command
AT+VNH = 1
or
AT+VNH = 2
in
the
initialization.
This
command
allows
the
transmitter
to
resend
the
data
without
causing
a
character
abort.
Once CAS is detected, the modem responds with CAS ACK. The
duration of CAS ACK is 60 ms.
CASRPT selects Auto or Manual mode for transmitting CAS ACK.
Auto mode (CASRPT = 0): Auto mode reduces the delay between CAS and CAS ACK. After an AT+FRM=200
command, the modem detects the CAS tones and sends CAS ACK without reporting CAS detection to the host.
Manual mode (CASRPT = 1): Manual mode allows the host processor to have more control. A modem reports to its
host with the string "CAS" when it detects CAS tones. The modem waits for the host to reply with the ASCII
character 'D', then it responds to the other modem with CAS ACK. If the host sends any character other than 'D',
the modem returns to the command mode immediately without sending CAS ACK and replies to the host with
<DLE><ETX>. This allows the host to send any DTMF digit.
The host can then send an AT+FTM command or an
AT+FRM command. If the host doesn't send any characters or commands, the modem will time out (as set by UD2)
and go back on-hook without sending CAS ACK.
9.2.2.1. Example
The host could use this sequence to set up the modem for Protocol 1 SMS:
13F4
–20
191E
–19
1F9F
–18
27D0
–17
321E
–16
3F19
–15
4F6F
–14
6400
–13
7DE4
–12
AT:UCA,1,0,4E
This sets up the modem for V.23 modulation, Protocol 1, 78
Mark bits in the message header.
AT+FTM=201
Transmit a Protocol 1 SMS frame
<CR><LF>CONNECT <CR><LF>
Modem response to the host
Table 162. UD4 SMS CAS Tone Detector Threshold Level (Continued)
UD4 (Hex)
CAS level (dBm)
Содержание Si2404
Страница 2: ...AN93 2 Rev 1 4 ...
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Страница 201: ...AN93 Rev 1 4 201 Figure 32 Si3000 Codec Gain and Signal Selection Options ...
Страница 290: ...AN93 290 Rev 1 4 Figure 57 256 Band Spectral Display Figure 58 2048 Band Spectral Display ...
Страница 305: ...AN93 Rev 1 4 305 Figure 76 Parallel or SPI Port Interrupt Service Flowchart ...