Multi-Tech Systems MT2456SMI22 manual Command Hex Codes Description Supported DTE-to-DCE Commands

			Chapter 4 - V.22bis Commands
Table of Supported V.80 Commands
	Command	Hex Codes	Description
		Supported	V.80 DTE-to-DCE Commands
	<extend0> <length>	<40h>	The DCE decodes this as a sequence of 3 + (<length>-1Fh).
	<control> <rest of command>	<42h>
	<105off>	<42h>	Circuit 105 is OFF.
	<105on>	<43h>	Circuit 105 is ON.
	<singleEMp>	<58h>	The DCE decodes this as one <99h> in user data.
	<doubleEMp>	<59h>	The DCE decodes this as <99h><99h> in user data.
	<singleEM>	<5Ch>	The DCE decodes this as on <19h> in user data.
	<doubleEM>	<5Dh>	The DCE decodes this as <19h><19h> in user data.
	<poll>	<5Eh>	The DCE decodes this command and deliver a set of status
			commands, one for each circuit enabled.
		Supported	V.80 DCE-to-DTE Commands
	<extend0> <length>	<60h>	The DCE decodes this as a sequence of 3 + (<length>-1Fh).
	<status> <rest of command>	<62h>
	<106off>	<62h>	Circuit 106 is OFF.
	<106on>	<63h>	Circuit 106 is ON.
	<125off>	<6Ah>	Circuit 125 is OFF.
	<125on>	<6Bh>	Circuit 125 is ON.
	<singleEMp>	<76h>	The DCE encodes this as one <99h> in user data.
	<doubleEMp>	<77h>	The DCE encodes this as <99h><99h> in user data.
	<singleEM>	<7Ch>	The DCE encodes this as on <19h> in user data.
	<doubleEM>	<7Dh>	The DCE encodes this as <19h><19h> in user data.

In Band Processing of AT Commands

When in-band control sequences are enabled, the modem responds to EM shielded AT commands via the extend-0 CONTROL sequence. This command may be used to transmit any AT commands to the modem as follows:

EM <extend-0> <length> <CONTROL> <AT Command without AT and trailing carriage return>

Upon receipt of an in-band command, the modem responds with the extend-0 STATUS REPORT sequence. This sequence will contain the response to the AT command issued via the CONTROL sequence with the trailing <cr> <lf> omitted:

EM <extend-0> <length> <STATUS> <AT Command response without trailing LF> Example: Send +VRID=2 command to the modem and respond with terse caller ID:

EM <60h> <27h> <42h> +VRID=2

Note: <length> is 27h corresponding to 27h-1Fh=8. This is the length of the sequence following the <length> octet. The modem responds to this command by transmitting the caller ID information to the DTE via the in-band sequence:

EM <60h> <length> <62h> <raw caller ID information> EM<60h><22h><62h>OK

In this case, the <length> octet is the actual length of the raw caller ID + 1 + 1Fh.

In Band Signaling of CTS and Ring Indicate (Circuit 106 and Circuit 125)

Whenever the V.24 circuit selected via the +IBC command changes, the modem will send an unsolicited EM shielded frame to the DTE to inform the DTE of the new state. This is used for CTS and RI. For MOH applications, the DTE is specifically interested in circuit 125 (Ring Indicate).

When RI is asserted, the sequence EM <125on> or 19h 6Bh is sent to the DTE. When RI is de-asserted, the sequence EM <125off> or 19h 6Ah is sent to the DTE.

Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 20