ch1786nh ETC-unknow, ch1786nh Datasheet - Page 8

• Manufacturer Part Number: ch1786nh
• Description: Ch1786 Family Ultra Small 2400bps Modems
• Manufacturer: ETC-unknow

Cermetek Microelectronics, Inc.
Note:
The escape sequence consists of a “guard time” (a
period where no characters are sent to the modem),
followed by 3 escape characters, followed by another
guard time. The guard time is set by register S12.
The escape character code is set in register S2. At
power-up, the guard time is set to 1 second minimum,
and the escape character is set as “+.” There is no
minimum delay between characters but the maximum
delay is set by register S12.
The CH1786 will stay off-hook with its carrier on after
the escape sequence is received. It will return an OK
2003 Cermetek Microelectronics, Inc.
PIN
18
19
20
21
22
Result Codes
(1) If VCC has a slow power up ramp time, the internal reset may be ineffective.
(2) Do not drive LED’s directly from any output. Use Buffers.
NAME
RST
GND
VCC
HS
NC
10
0
1
2
3
4
5
6
7
1
TYPE
O
-
-
I
-
OK
CONNECT
RING
NO CARRIER
ERROR
CONNECT 1200
NO DIAL TONE
BUSY
CONNECT 2400
Table 3. Summary of Result Codes and Meanings.
No connection required. For CH179X or CH2056 compatibility, connect to GND or
SPEED INDICATION. HIGH speed select output. A low on this pin indicates the
modem is operating at 2400bps.
POWER SUPPLY. 5 volts + 5% Note: Noise should be less than 50mV peak to
peak.
GROUND. Note: Noise should be less than 50mV peak to peak.
RESET. Active HIGH. This input must be asserted HIGH for at least 10 ms to reset
the modem. RESET is then returned LOW for normal operation. If no system reset
is available, let this pin float to enable internal reset.
use as an active LOW input for request to send (RTS) functionality for CH179X/2056
products.
Table 2. CH1786 Pin Descriptions Continuation
Status Message
Page 8
status message when it is ready to accept
commands. The CH1786 may be put into data mode
by issuing the command ATO<CR>.
AT COMMAND APPLICATIONS
Dialing A Phone Number. The Dial command takes
the form Dn, where n is a string of characters. In the
simplest form, n will be only the digits of the phone
number to be dialed.
Example: Dial number.
Enter:
Carrier detected at 300bps
Command Executed
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
FUNCTION
ATD1234567<CR>
CH1786 Family of Ultra Small 2400bps Modems
Document No. 607-0004 Revision L1 (06/03)
Meaning