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AT Commands Description | |
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1. AT Commands Description AT commands are issued to Pace ISDN TA to control its operation and software configuration. AT commands can only be entered while the modem is in command mode. The format for entering AT commands is: TYPE: ATXn where X is the AT command, and n is the specific value for that command. PRESS: Enter Any command issued is acknowledged with a response in either text or numeric values known as result codes. These are described in details further in this manual. In the following listing, all commands and command values accepted by Pace ISDN TA are described. any entries other than those shown cause the ERROR result code. +++ Escape Sequence The escape sequence allows Pace ISDN TA to exit data mode and enter on-line command mode. While in on-line command mode, you may communicate directly to Pace ISDN TA using AT commands. Once you are finished, you may return to data mode using ATO command. A pause, the length which is set by the Escape Guard Time (S12), must be used before and after an escape sequence is issued. This pause prevents the modem from interpreting the escape sequence as data. the value of the escape sequence character may be changed using register S2 1.1 General Service Selection These commands and parameters allow to select the general behaviour of Pace ISDN TA.
1.2 Call Control These commands and parameters are used for setting up and clearing an ISDN call (or an analogue GSTN call).
1.2.1 Pace ISDN TA DTE Channels In your Pace ISDN TA TA, the following DTE channels and associated number ID are defined:
1 : Asynchronous transparent using X.25/PAD to X.25/PAD (special PAD profile) with optional V.42bis data compression.
6 : Telephony (used only as a test case).
7 : PPP asynchronous to synchronous conversion (ISO 4335 HDLC Addendum).
8 : Asynchronous transparent using V.14 rate adaptation (padding with STOP bits).
10 : Asynchronous transparent using V.120 rate adaptation with V.42bis data compression (negotiation according to ITU standard). DTE-Channel 10 is the factory default DTE channel
11 : X.25/PAD through one B channel connected to an PSDN through a gateway.
12 : X.25/PAD through the D channel (SAPI 16, Manual TEI).
13 : Asynchronous transparent through 2xB aggregated channels and using V.120 rate adaptation, X.25 MultiLink Procedure, and V.42bis data compression.
14 : X.25/VideoPAD through one B channel.
15 : X.25/VideoPAD though the D channel (SAPI 16, Manual TEI).
Each DTE CHANNEL can support one or several calls according to the services. Each call is identified by a global call ID number. The current DTE channel is selected using &O command or through the setting of the S110 register. The default DTE channel is set using the configuration parameter « #default_dte_channel ». The factory default DTE channel is 10 (asynchronous transparent using V.120 rate adaptation).
1.2.2 Examples of Dial Commands
The outgoing call is, by default, established on the currently selected DTE channel. Use the &O command to select the DTE channel. S110 contains the identifier of the current DTE channel. By extension, it is possible to 'dial ' on a D-channel, that is, to request establishment of an X.25 virtual circuit in D-channel packet mode. In this case, the ISDN address must be 'D' or 'd', or must be empty.
Also, it is possible to dial using a specific DTE channel, specified in the dial string. In this case, the DTE channel number is supplied after the X.25 address, introduced by a colon.
The general syntax for a dial command is therefore :
ATDisdn_nb*sub_addr[&isdn_nb2]:x25_addr:dte_channel_id
where:
isdn_nb*sub_addr is an ISDN number, followed by an optional subaddress. If this field is empty, or replaced by 'D' or 'd', X.25 virtual circuit establishment is requested on the D-channel.
isdn_nb2 is used for establishing a 2 B channels call (DTE channel 13) in North America when connected to a DMS-100 switches. Only the last different digits can be provided, the number is padded according to the first number.
x25_addr is an X.25 address. If this field is empty, address 0 is used. This field is unused if the call is not for an X.25 communication.
dte_channel_id is the number of the DTE channel to use. If this field is empty, the current DTE channel is used.
These extensions to the dial command allow a DTE 'modem' application to run and drive all the services offered by Pace ISDN TA, without modifications of the application. The extended dial strings (which now contains 'service' information) can be stored in the application's directory.
Dialing over an ISDN access
ATD69855044 calls the ISDN address 69855044
ATD69855044*5 calls the equipment at ISDN address 69855044, with subaddress 5.
ATD&O13
ATD69855044*5&5 calls the equipment at ISDN address 69855044 and 6985045, with subaddress 5.
Dialing over an ISDN access, using a PAD DTE channel
ATD36086464:1750123456 calls the ISDN address 36086464 (in this case, ISDN address of the ISDN access point to the Transpac X.25 public network), and establish a virtual circuit (X.25 call) with the equipment at X.25 address 1750123456. ATD69855044 calls the X.25 equipment at ISDN address 69855044, establish a virtual circuit using the default X.25 address (typically 0). This command is useful for performing point to point, PAD to PAD, data transfer. Bit 5 of register S112 must be set to 1. If this bit is set to 0, the virtual circuit is not established, when the ISDN call is established the PAD prompt is presented to the user. ATD69855044*4:1750123456 669855044 is the ISDN address, 4 is the ISDN subaddress, 1750123456 is the X.25 address.
Establishing a PAD/X.25 communication on the D-channel
ATD:1750123456 or Establish a virtual circuit with the X.25 equipment at X.25 address 1750123456, ATDD:1750123456 using D-channel packet mode
Establishing communications, with DTE channel specification
ATD36086464:1750123456:11 Use DTE channel 11 to perform the X.31 case A outgoing call.
ATD:1750123456:12 Use DTE channel 12 to perform X.25 connection establishment on the D- channel. ATD69855044*2::1 DTE channel 1 is a PAD DTE channel, use DTE channel 1 to perform an ISDN call, followed by an X.25 (DTE-DTE) virtual circuit establishment.
If DTE channel 6 is a telephony DTE channel, use DTE channel 6 to perform a telephony outgoing call.
1.2.3 Extended Call Control
The following commands are 'extended' call commands for ISDN. They allow to manage several calls simultaneously. The following lexical elements are used :
call_id : Integer, call identifier.uui: User to user information. When present, delimited by quotes. Example : "Hello". addr, addr*sub, addr*sub&addr: ISDN address and subaddress. A star '*' separates the address and subaddress. Subaddress is optional. In case of V.120 MLP or ML PPP using 2 B channel a second address can be added using « & » separator. Only the last digits of the second address is required. The first digits are copied from the first address. rate: Rate of the data in B channel 64 or 56 kbps. x25_addr: Optional X.25 address. When present, introduced by a colon ':'. cause: Call clearing cause, two hexadecimal digits.
Examples : 123 dial number 123 123*456 dial 123 subaddress 456 12345678*13&9 dial 12345678 and 12345679 with with address 13.
1.2.4 Examples of Extended Call Control Commands
Suppose we have an Pace ISDN TA with the following configuration : - DTE channel 6 is a voice DTE channel (S111 is 1), able to support one call, with (call) user reference 6. - DTE channel 11 is a PAD DTE channel (S111 is 7), able to support one call, with user reference 11.
Suppose also that, for both channels, S112 is set to 35 (maximum information and PAD automatic VC establishment). Indications sent by Pace ISDN TA are in italic:
Establishment of two successive voice calls
AT&O6*D/11 select DTE channel 6, dial ISDN address 11. OK:6,0,6 immediate acknowlegment, call 6 is being established on network access 0 and DTE channel 6. PROGRESS:6,0,0,6,1 Progress indication for call (6) DTE channel 6 channel B1 due to interworking with analogue telephone network. ALERT:6,0,6,1 Called terminal RINGING and returning ALERT indication. CONNECTED:6,,0,6,1 First call (6) is established, B1 channel is selected. CLEARED:6,10 Clear of call (6) with a normal cause (10).
AT*D/69855044*5/"Hello" while the first call is being established, call the equipment at ISDN address 69855044 and ISDN subaddress 5, and transfer the user to user information "Hello". Note that there is no need to enter an &O6 command, current DTE channel is already DTE channel 6. OK:6,0,6 Immediate acknowlegment, call 6 is being established on network access 0 and DTE channel 6. CONNECTED:6,"Welcome",0,1,2 Second call (6) is established, B2 is selected. The remote has AT*H0/6 Clear the call 6.
Establishment of a PAD call (see also examples related to the D command)
AT&O11*D/36086464:1750123456 Select DTE channel 11, dial ISDN address 36086464 (ISDN access point to the Transpac X.25 network), call the equipment at X.25 address 1750123456
OK:11,0,11 Iimmediate acknowlegment, call 11 is being established on network access 0 and DTE channel 11
CONNECTED:11,,0,11,1 call (11) is established, B1 channel is selected
(CD ON) virtual circuit is established
DTE controlled answer to two incoming voice calls
DTE channel 1 is not in auto answering mode (S0 = 0)
RING:6,1,,44332211*2,0,1,6,1,5044
Incoming call, call number 6, voice service (1), no UUI sent by the remote calling equipment, calling address and subaddress : 44332211, 2, network access 0, DTE channel 6, B channel B1, called address (as supplied by the ISDN) is 5044. We decide not to answer now, and let the call ring. second incoming call, call number 1, Pad service (7), UUI AT&O1*A1,"Welcome" we decide to answer to the second call. We first select DTE channel 1 (&O1), answer to call number 1 and send the UUI "Welcome".
CONNECTED:1,,0,1,2 call (1) is established, B2 channel is selected.
CLEARED:6,10 first call (6), which was still ringing, is terminated (for example, the remote end rejected the call).
Automatic answer to two incoming calls for different services
DTE channel 6 and 11 are autoanswering (S0 = 1 for both DTE channels) RING:6,1,,44332211*2,0,6,1,5044 Incoming call, call number 6, voice service (1), no UUI sent by the remote calling equipment, calling address and subaddress : 44332211, 2, network access 0, DTE channel 6, B channel B1, called address (as supplied by the ISDN) is 5044.
CONNECTED:6,,0,1,1 Call (6) is automatically established on DTE channel 1, B1 channel.
RING:11,7,,88877766,0,11,2,5044
Incoming call, call number 11, PAD service (7), no UUI sent by the remote calling equipment, calling address : 8887766, network access 0, DTE channel 11, B channel B2, called address (as supplied by the ISDN) is 5044.
CONNECTED:11,,0,11,2 Call (11) is automatically established on DTE channel 2, B2 channel.
1.3 DTE-DCE Interface
These commands and parameters allow to set up the DTE-DCE port.
1.4 General Control, Profiles and Identification
1.5 Test Commands
These commands and parameters are useful for testing.
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