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<TITLE><DLE>-shielded codes</TITLE>
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<B><FONT SIZE=+2><DLE></FONT>-SHIELDED <FONT SIZE=+2>C</FONT>ODES</B>
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In voice transmit/receive mode, BISYNC protocol should be
applied to the data stream to/from the DCE. During this period,
commands and responses will be in <DLE> shielded form. The supported
<DLE> shielded codes are as follows (all <DLE> shield codes are case
sensitive):
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<B><FONT SIZE=+2>C</FONT>OMMANDS</B>
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Code Simple Action Command Description
------- --------------------------------------------------
<NUL> This is something I would recommend
<DLE> <CITE>Complies with IS-101</CITE>
p Pause Transmit Data State("Immediate Command").
<CITE>Complies with IS-101</CITE>
r Resume Transmit Data State("Immediate Command").
<CITE>Complies with IS-101</CITE>
<ETX> End Transmit Data State ("Stream Command").
<CITE>Complies with IS-101.</CITE>
<CAN> Clear transmit buffer of voice data("Immediate Command").
<CITE>Complies with IS-101.</CITE>
<FS>or<DC2> Concatenate transmit data streams("Stream Command").
<CITE>Complies with IS-101.</CITE>
<DC4> Clear transmit buffer of voice data and return to command
mode("Immediate Command"). <CITE>Not defined in IS-101.</CITE>
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<B><FONT SIZE=+2>R</FONT>ESPONSES</B>
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Code Event Report Description
------- --------------------------------------------------
<DLE> Two contiguous <DLE><DLE> codes indicate a single
<DLE> in the data stream. Complies with IS-101
<ETX> End Data State. Complies with IS-101
0 DTMF '0' received. Complies with IS-101
1 DTMF '1' received. Complies with IS-101
2 DTMF '2' received. Complies with IS-101
3 DTMF '3' received. Complies with IS-101
4 DTMF '4' received. Complies with IS-101
5 DTMF '5' received. Complies with IS-101
6 DTMF '6' received. Complies with IS-101
7 DTMF '7' received. Complies with IS-101
8 DTMF '8' received. Complies with IS-101
9 DTMF '9' received. Complies with IS-101
# DTMF '#' received. Complies with IS-101
* DTMF '*' received. Complies with IS-101
c T.30 Facsimile Calling Tone. Complies with IS-101
e Data Calling tone. Complies with IS-101
s "Presumed Hangup"(Silence) Time-out.
Silence detected. The DCE has determined that there
was no voice energy present at the the beginning of
the voice recording session followed by a period of
silence greater than the amount of time selected by
AT+VSD command. Complies with IS-101
q "Presumed End of Message" (Quiet) Time-out.
Quiet detected. The DCE has determined that there was
voice energy present at the the beginning of the voice
recording session followed by a period of silence
greater than the amount of time selected by AT+VSD
command. Complies with IS-101
b Busy tone. Complies with IS-101
d Dialtone tone. Complies with IS-101.
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<B><FONT SIZE=+2>D</FONT>ESCRIPTION</B>
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<I>DTE to DCE stream</I>. The DCE will filter the data stream from the DTE and
remove all character pairs beginning with <DLE>. The DCE will
recognize <DLE><DLE> and reinsert a single <DLE> in
its place. The DTE must filter stream data to the DCE, and insert extra
<DLE> characters ahead of <DLE> data.
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<LISTING>
+--------------+
| TDA=Tx Data |
+--------------+
|
+------------+
| TDA=DLE ? |
+------------+
|
+--------------------+
YES| |NO
+--------------+ +--------------+
| Send two DLE | | Sned TDA to |
| to UART | | UART |
+--------------+ +--------------+
</LISTING>
<I>DCE to DTE stream</I>. The DTE must filter the data stream from the DCE and
remove all character pairs beginning with <DLE>. The DTE must
recognize <DLE><ETX> as the stream terminator. The DTE must
recognize the <DLE><DLE> and reinsert a single <DLE>
in its place. The DCE will filter stream data to the DTE, and insert
extra <DLE> characters ahead of <DLE> data.
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<LISTING>
+--------------+
| RDA=Rcv Data |
+--------------+
|
+------------+
| PREVDLE=1? |
+------------+
|
+---------------------------+
YES| |NO
+-----------+ +-----------+
| PREVDLE=0 | | PREVDLE=0 |
+-----------+ +-----------+
| |
+----------+ +-----------+
| RDA=DLE? | | RDA=DLE ? |
+----------+ +-----------+
| |
+-----------+ +-----------------+
YES| |NO YES| |NO
+----------+ +-----------+ +-----------+ +-----------------+
| Put RDA | | Check for | | PREVDLE=1 | | Is it Tx mode ? |
| into Buf | | Command | +-----------+ +-----------------+
+----------+ +-----------+ |YES
+-------------------+
| Check if XON/XOFF |
+-------------------+
|
+--------------+
YES| |NO
+-----------+ +----------+
| Handle | | Put RDA |
| Flow Cntl | | into Buf |
+-----------+ +----------+
</LISTING>
<P>
<A HREF="@HTMLPATH@/Modems/ZyXEL/examples.html"><IMG SRC="@HTMLPATH@/icons/next.gif"> Examples of voice mode operation</A>.<BR>
<A HREF="@HTMLPATH@/Modems/ZyXEL/voice.html"><IMG SRC="@HTMLPATH@/icons/back.gif"> ZyXEL Advanced Voice Capability</A>.
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<ADDRESS>
<A HREF="@HTMLPATH@/sam.html">Sam Leffler</A> / <A HREF="mailto:sam@engr.sgi.com">sam@engr.sgi.com</A>.
Last updated $Date: 1998/10/12 20:47:51 $.
</ADDRESS>
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