Making a Call, Answering a Call | Multi Tech Equipment MTA128ST

AT Commands, S-Registers, and Result Codes

Making a Call

Before you can place a data call, configure the MTA1 28ST/NT for the local switch type, serial port speed, and the data type of the ISDN device you want to call. See Chapter 3, Configuration Utilities.

Dialing

To dial a number using AT commands, you must first start a data communications program. In the program’s terminal mode, type ATDxxxxxxx<cr>, where xxxxxxx is the telephone number you want to dial, and <CR> is the carriage return character that is sent when you press the ENTER key, such as ATD7853500<cr>. The dial string can contain up to 80 characters.

To place an ML-PPP call, use an ampersand character (&) to join two telephone numbers, such as ATD7853500&7853502<cr>. The telephone numbers can be the same or different. Using this method, two B-channels are activated to transmit data at an aggregate speed of 128 Kbps.

To make it easier to read the dial string, you can use hyphens, spaces or parentheses. These characters are ignored by the MTA1 28ST/NT. For example, the MTA1 28ST/NT would read the following dial strings the same way:

ATD17637853500 <cr>

ATD 1-763-785-3500 <cr>

ATD 1 (763) 785-3500 <cr>

Channel Bundling Flag Dialing

The command AT&Jn is used to indicate whether outgoing calls should be made on two B-channels by default. The command AT&J1&W0<cr>, configures the TA to place a call, dialing on two B-channels by default. If no second number is given in the dial string, that single number is dialed twice. This compensates for the interworking issues with Windows Dial-Up Networking. On the other hand, if the user explicitly indicates two numbers in the dial string, then two numbers are dialed (e.g., ATD7853500&785 3502<cr>). The command AT&J0&W0<cr>, disables automatic call bundling. Note other valid characters joining two telephone numbers include a plus sign (+), and an exclamation mark (!).

Note: In Windows Dial-Up Networking, if the Use Country Code and Area Code box is checked in the Properties window for dial-up connection, the bundling modifier (i.e., &, + or!) is removed from the dialing string when the user attempts to make a connection. The solution is to not check the Use Country Code and Area Code box or to simply add the bundling dial modifier to the phone number at the time of connection.

Canceling a Call

To cancel a call before the MTA128ST/NT makes a connection, press any key.

Storing a Telephone Number

To store a telephone number, type &Zn=x in terminal mode, where n is the number of the memory register in which the number is to be stored, and x is the dial command string that you want to store. For example, type AT&Z9=763-785-3500 <cr> to store the number 763-785-3500 in memory register 9.

Dialing a Stored Telephone Number

To dial a stored telephone number, type DSn in terminal mode, where n is the location of the number you wish to dial. For example, type ATDS3 <cr> dials a telephone stored in memory register 3 location.

Displaying a Stored Number

To display a stored telephone number, type &Zn? in terminal mode, where n is the memory register in which the number is stored. For example, type AT&Z5? <cr> to display the telephone number in memory register 5. To list all ten telephone numbers stored in memory, type ATL <cr>.

Answering a Call

You can answer incoming calls to the MTA128ST/NT either manually or automatically. When the TA detects an incoming call, it turns on the RI signal on the V.24 interface and sends a RING result code to the computer or terminal after each ring. If autoanswer is enabled, the TA automatically answers the call. You can manually answer the call with the A command. Both methods are described below.