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參數(shù)資料
| 型號： | CH1793 |
| 英文描述： | MODEM |
| 中文描述： | 調(diào)制解調(diào)器 |
| 文件頁數(shù)： | 5/16頁 |
| 文件大小： | 1942K |
| 代理商： | CH1793 |
2000 Cermetek Microelectronics, Inc.
Page 5
Document No. 607-0003 Revision G (05/00)
AT [commands] [CR].
Where:
[AT]
represents attention sequence.
[commands]
represents command strings.
[CR]
represents carriage return (ASCII 13 or HEX 0D).
When entering commands to the modem, the backspace
character-control-H (ASCII 8 or HEX 08) can be used to edit
mistakes. “AT” and “A/” may not be edited however. Multiple
commands may be placed in the command line. A command
line may be as long as 40 characters, excluding the letters
AT. By way of example, the command below instructs the
HS Modem to configure itself to not echo characters when in
command mode (E0) and then put itself in answer mode (A).
Enter:
ATE0A[CR]
AT Command Set.
The available command set is divided into four types of
commands: dial modifiers, basic commands, ampersand and
percent commands. Refer to the complete list in Tables 6A
and 6B.
INITIALIZING THE MODEM
Before commands may be sent to the HS Modem, the
modem must be initialized. This consists of two events:
1.
Modem Reset. This is accomplished by applying a
hardware reset pulse to pin RST or by switching the
power off and then back on.
2.
Initial Modem Training. The modem must be trained to
the host DTE speed and parity (odd, even, mark, space
or none). These activities are briefly described below.
Reset.
Upon applying power to the HS Modem, the HS Modem
automatically generates an internal reset pulse. The user
can also reset the modem externally by applying a high-going
reset pulse to the RST pin for at least 10ms after the +5V
power supply has stabilized. Delay sending commands to
HS Modem for 900ms after reset has been initiated to allow
the HS Modem time to properly reconfigure.
On power up, or when reset is initiated either by command
(ATZ) or by the RST pin, the modem will reconfigure to its
default state with the line carrier modulation speed set to:
1.
2.
3.
4.
14.4kbps for the CH1794
28.8kbps for the CH1798
33.6kbps for the CH1799
56.0kbps for the CH2056
If desired, any speed, error correction, or data compression
method available on the HS Modem can be locked in, using
the AT\Nn and/ or AT+MS commands.
Training the Modem.
Each modem must be trained to match the host DTE speed
and parity so that it is able to recognize serial asynchronous
commands sent to it by the DTE.
The DTE must retrain the modem each time a reset pulse is
applied on RST or after a RESET serial command has been
issued.
Modem Training Command Sequence.
The HS Modem is trained by sending it the following
sequence:
Enter:
Where:
A
and
T
may be either upper or lower case but
must be the same case.
[CR]
represents carriage return
AT[CR]
The “AT” sequence is referred to as an attention sequence.
The HS Modem will respond with one of the following status
messages, depending on whether it is optioned for
abbreviated or English status messages.
Result:
0[CR]
(Abbreviated form)
Result:
[CR][LF][OK][CR][LF]
(English form)
Where:
[CR]
represents carriage return (ASCII 13 or
HEX 0D).
[LF]
represents line feed (ASCII 10 or HEX 0A).
The modem is now in idle mode and is ready to accept
commands.
An alternate attention sequence “A/” may be sent which
behaves much like the AT sequence except that it causes
the previously entered command specified with an AT prefix
to be executed. When given, it must be in upper case
ASCII. No carriage return is needed.
STATUS MESSAGES AND RESULT CODES
A result code is issued by the HS Modem to the DTE for all
commands executed by the HS Modem, except dialing
commands. Further, various activities on the PSTN are also
signaled to the DTE by the HS Modem.
All result codes have either a terse, short form version
(which is identified by a number followed by a [CR]) or a
verbose long form English-like message version (which is
preceded and terminated with a [CR] and line feed).
The user may suppress certain subsets of the non-extended
result codes. This is accomplished by selecting subsets of
the result code set using the ATXn command, where n=0, 1,
2, 3. Optionally, the user may specify an extended set of
result codes (codes above 35) by setting Register S95. See
the detailed description of result codes in Table 5A, Table
5B and Table 5C.
All AT commands, other than dialing commands, will be
responded to with either an OK (short form result code 0) if
the command is valid or accepted, or with an ERROR (result
code 4) if the command is not recognized. The detail
contained in the error result codes signaled to the DTE
depends on the level of message suppression employed by
the user. As can be seen from Tables 5A, 5B and 5C,
specifying X4 allows the HS Modem to utilize the entire
range of non-extended messages, whereas X0 suppresses
all but the very basic result codes. Most of the result codes
allowed under X1, X2 and X3 are considered call progress
status codes and, in practice, are suppressed except for the
case of debugging activities. It is recommended that the
non-extended result codes be used in all cases.
It should be noted that the default connect result codes 9-20
indicate DTE connection speed, not Carrier Line DCE
speed. Hence, a CH1794 will connect at a maximum speed
of 19.2kbps (result code 16). The CH1798 and CH1799 will
connect at a maximum DTE speed of 38.4kbps (result code
17) and the CH2056 will connect at a maximum speed of
57.6kbps (result code 18) unless the DTE is forced to a
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| CH1793ET | Telecommunication IC |
| CH1793LT | Telecommunication IC |
| CH1798 | Telecommunication IC |
| CH1798ET | MODEM |
| CH1799ET | MODEM |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| CH1793ET | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Telecommunication IC |
| CH1793LT | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Telecommunication IC |
| CH1794 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:HIGH SPEED Modem and FAX FAMILY |
| CH1794A | 制造商:Cermetek Microelectronics 功能描述:Modem Chip Single 57.6Kbps 22-Pin |
| CH1794A ET | 制造商:Cermetek Microelectronics 功能描述:Extended Temp. CH1794A, -40 oC - +85oC |
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