CH1787 데이터 시트보기 (PDF) - Cermetek Microelectronics
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CH1787 Datasheet PDF : 14 Pages
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Cermetek Microelectronics, Inc.
CH1787 Small Footprint Hardware Controllable 2400bps Modem
AT [commands] <CR>. Where <CR> represents
carriage return (ASCII 13). When entering commands
to the CH1787, the backspace character CTL H (ASCII
8) can be used to edit mistakes. AT and A/ may not be
edited. Multiple commands may concatenated on a
single command line. Command lines may not exceed
40 characters, excluding AT. The command string
below instructs the CH1787 to train itself, to not echo
characters in the command mode E0 and then go to the
answer mode A.
Enter:
Response:
ATE0A<CR>
OK <CR><LF>
AT COMMAND DATA RATE
With the serial interface, the rate is speed sensed for
parity and format.
AT COMMAND SET
The command set is divided into three types as listed in
Table 2: basic commands, dial modifiers and
ampersand commands.
“+.” These parameters can be modified via registers S2
and S12, respectively.
The CH1787 will stay off-hook with its carrier on after
the escape sequence is received. It returns an OK
status message when it is ready to accept commands.
The data mode is reentered by issuing the ATO
command.
Result
0
1
2
3
4
5
6
7
10
Status
Messages
OK
Connect
Ring
No Carrier
Error
Connect 1200
No Dial Tone
Busy
Connect 2400
Meaning
Command executed.
Carrier detected at
300bps.
Ring detected.
Did not detect carrier.
Entry error.
Carrier detected at
1200bps.
Off-hook, but no response
after 5 seconds.
Busy signal detected.
Carrier detected at
2400bps.
THE STATUS MESSAGES
The CH1787 responds with a status message after
each command is executed. This status message may
either be a single digit followed by a carriage return or a
carriage return and line feed with a message in English,
followed by a carriage return and line feed.
The basic status code subsets are enabled with the Xn
command. Where n=0,1,2,3,5 the status codes can be
in message form or result codes selected for the five
Xn commands.
X0 – Result Codes 0, 1, 2, 3, 4
X1 – Result Codes 0, 1, 2, 3, 4, 5, 10
X2 – Result Codes 0, 1, 2, 3, 4, 5, 6, 10
X3 – Result Codes 0, 1, 2, 3, 4, 5, 7, 10
X4 – Result Codes 0, 1, 2, 3, 4, 5, 6, 7, 10 (factory
default)
Modem States. The CH1787 may be in either the
Command mode or the Data Mode. When the CH1787
is idle, it is in Command Mode by default. When a data
transmission is in progress, the CH1787 is in Data
Mode and will not recognize commands. The host
system must send an “escape sequence” to the
CH1787 forcing it out of the Data Mode and into the
Command Mode before commands will be accepted.
Escape Sequence. The escape sequence consists of
a guard time (a period where no characters are sent to
the CH1787) followed by 3 escape characters, followed
by a guard time. At power-up, the guard time is set to 1
second (minimum), and the escape character is set as
Dial Modifiers
P
R
T
W
;
@
!
,
0-9/ A,B,C,D
Function
Pulse Dial
Originate Call in Answer
Mode
Touch Tone Dial
Wait for Dial Tone
Return to Idle State
Wait for Quiet Answer
Command
Flash Hook
Pause
Dial Digits/Characters
AT COMMAND APPLICATIONS
Dial A Number. The Dial command takes the form
Dn, where n is a string of characters. In the simplest
form, n will only the digits of the phone number to be
dialed.
Example: Dial number
Enter: AT D 1234567<CR>
In response to this command, the CH1787 dials the
telephone number “123-4567” and then waits for the
carrier from the remote modem. If no carrier is
detected within a given time (the default time is 30
seconds), the CH1787 automatically releases the line
and sends a NO CARRIER result code. If a carrier is
detected, the CH1787 issues a CONNECT result code
and goes on-line, permitting communication with the
remote modem.
2002 Cermetek Microelectronics, Inc.
Page 6
Document No. 607-0002 Revision B (03/02)
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