18)
Enter AT+SER <CR> The unit responds with SERVICE AVAILABLE.
Using the CDL 900 to communicate
To use the CDL 900 to communicate with a modem, perform the following steps:
1)
Enter ATDT XXXX <CR>
XXXX is the phone number of the modem you are calling. After approximately 30
seconds, the CDL 900 responds with CONNECT message.
2)
Type “ Hello how are you”
The party you called should see the message on their terminal screen.
3)
Ask the called party to type a message and you should see that on your terminal
screen.
4)
Enter the Escape se++
The modem responds OK.
5)
Enter ATH0<CR>
The CDL 900 responds “No Carrier “ indicating that the connection is
terminated.
6)
Ask the remote party to dial you MIN number.
CDL 900 responds with CONNECT message after approximately 30 seconds.
7)
Repeat steps 2 to 5.
Theory of Operation
The CDL-900 is always in one of the two states:
•
Command state
•
Online state
This section describes the two states.
Command State
The CDL 900 assumes the Command state when it is turned ON. In this state, you can
configure the unit for a particular application. In the Command State, all inputs from the
PC are treated as commands.
Command guidelines
Command line is a string of characters sent from the DTE (example PC) when the unit is
in the Command state. All commands must adhere to the following guidelines
•
Command lines must have a prefix , a body and a terminator.
•
Command lines must begin with a character sequence AT.
•
Command Lines must end with Carriage return (CR).
•
Either all upper case or all lower case characters must be used.
•
Each command must be entered separately.
•
Command buffer is 40 characters.
Note:
Commands entered incorrectly or with out-of-range parameters will result in
ERROR message. Commands entered correctly will result in OK message.
Result Codes
Result Codes refer to the responses of the CDL 900 unit to a command.
Unless the CDL 900 has been programmed to be in the Quiet mode (explained later in
the AT command section), the unit will respond each time a command is issued. The
default mode of the CDL 900 is the Verbose mode. The responses in verbose mode are
characters.
