Line 6 AX2 212 User's Manual

Line 6 AX2 212 MIDI Specification

The AX2 212 MIDI interface allows control over program and bank selection, the use of
controllers for wah, volume, and modulation, and system exclusive commands for
editing and program dumps. Since the AX2 212 is not a sound generator, status
messages for note off (8xH), note on (9xH), poly pressure (AxH), channel pressure
(DxH), and pitch bend (ExH) are ignored when received, and never transmitted.
Controllers (BxH) and program change commands (CxH) are received and transmitted
on the MIDI channel set by the user (or modified via MIDI by using sysex commands). If
the MIDI channel is set to omni, the AX2 212 will receive commands on all channels,
and transmit on channel 1. For additional information on the specific parameters and
features of the AX2 212, please refer to the AX2 212 User Manual.

Volume control

The volume control of the AX2 212 is transmitted as controller 7 any time the volume
footpedal is moved. The volume can be controlled via MIDI with either controller
number 7 or 11 (both are always received). Note that if the current program is set with
the volume pedal disabled, the MIDI controller changes will have no affect.

Wah control

The wah control of the AX2 212 is transmitted as controller 4 any time the wah
footpedal is moved. The wah can be controlled via MIDI with either controller number
3 or 4 (both are always received). Note that if the current program is set with the wah
pedal disabled, or to a non-pedal controlled wah such as auto-wah, the MIDI controller
changes will have no affect. The user can also set the wah pedal to control any one of
most of the parameters instead of functioning as a wah. MIDI control of the selected
parameter is then also possible, via controller 3 or 4.

Bank Select

The AX2 212 will respond to controller 0 or 32 as a bank select command. It will take
the least significant bit of either controller value, and use it to select a program bank. If
the bit is 0, the preset bank is selected. If the bit is 1, the user bank is selected. The
change does not take affect until a program change command is received. Bank select
commands are not transmitted from the AX2 212.

Program Change

The AX2 212 responds to program change values of 0 to 127, and selects the
appropriate program from the current program bank. The AX2 212’s programs are
organized as 32 sets (called Sound Banks, and numbered 01 through 32) of 4 programs
(called Sounds A, B, C, and D). MIDI program number 0 relates to program 01A, MIDI
program number 1 selects program 01B, and so on. MIDI program number 127 will
select program 32D. The AX2 212 will transmit a program change command any time
the user selects a new program from the front panel or the Floor Board foot controller.
Note: The user can select one received program number to be specified as a tuner

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select command, so that the tuner can be turned on via a MIDI program command.
This can also be edited via MIDI sysex control of the global parameters, described later.

Universal System Inquiry

The AX2 212 will respond to the universal system inquiry command if the channel
received is the same as the AX2 212’s MIDI channel, the channel received is 7F (all
channels), or the AX2 212 is set to omni mode. The received message is in the
following format:

F0 7E <chan> 06 01 F7 System inquiry message

If the channel received is 7F, the AX2 212 will respond with the channel also set to 7F.
If the channel received is not 7F, the AX2 212’s response will contain the same channel
as was received. The response transmitted from the AX2 212 is in the following format:

F0 7E <chan> 06 02 System inquiry response
00 01 0C Line 6 manufacturer's ID
00 00 AX2 212 product family code
00 00 AX2 212 device family member code
xx xx xx xx Software version number (ASCII)
F7 End of system exclusive

The software version is a four digit ASCII code, with an assumed decimal point between
the second and third digit. For example, version 1.05 would be represented by 30H
31H 30H 35H. Note: All received universal system commands are ignored while the
AX2 212 is in tuner mode.

System Exclusive

System exclusive commands are used for sending and receiving programs, global
settings, and for editing specific parameters. All transmitted and received sysex
commands contain the same first five bytes:

F0 Sysex command
00 Line 6 ID msb
01 Line 6 ID mid
0C Line 6 ID lsb
00 AX2 212 ID

The next byte (sixth byte) contains the opcode for the desired sysex command. There
are currently six opcodes supported, and they are summarized here along with their
data format:

00 Program dump

<program #> <83 bytes program data...> F7

01 Edit buffer dump

00 <83 bytes program data...> F7

02 Global buffer dump

<48 bytes global data...> F7

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03 Sysex dump request

<type> {<program #>} F7
{} may be omitted depending on type:

<type>=0 (program), <program #>=0..127
<type>=1 (edit buffer), no <program #>
<type>=2 (global data), no <program #>
<type>=3 (all programs), no <program #>
(responds with 128 programs + global data)

04 Parameter edit

[<parameter #> <dataLSNibble> <dataMSNibble>] F7

Data in [...] can be repeated

05 Store edit buffer

<program #> F7

Note: All received universal system commands are ignored while the AX2 212 is in
tuner mode.

Program and Editing Formats

When sending or receiving a program or edit dump, the data is packed in the following
format so as to minimize the amount of bytes required to transmit the program. For
each 7 consecutive bytes of a program (labeled a through g below), 8 MIDI bytes are
sent, as follows:

Bit #

7 6 5 4 3 2 1 0 Byte
00 a7 a6 a5 a4 a3 a2 a1 Byte 0

00 a0 b7 b6 b5 b4 b3 b2 Byte 1
00 b1 b0 c7 c6 c5 c4 c3 Byte 2
00 c2 c1 c0 d7 d6 d5 d4 Byte 3
00 d3 d2 d1 d0 e7 e6 e5 Byte 4
00 e4 e3 e2 e1 e0 f7 f6 Byte 5
00 f5 f4 f3 f2 f1 f0 g7 Byte 6
00 g6 g5 g4 g3 g2 g1 g0 Byte 7

Since there are a total of 72 bytes per program (prior to this packing format), 83 bytes
of data are required to be sent out MIDI once converted to this format. When
combined with the sysex header and EOX, the total number of bytes transmitted per
program is 91 bytes.

All parameters are stored as 8-bit values. If the parameter range allows negative
numbers, the parameters is stored as a 2’s compliment 8-bit number. There are 72
bytes stored with each program, each byte representing one parameter. The first 66
bytes relate to the 11 rows of six parameters, in order, starting from the top left-most
parameter as printed on the AX2 212 front panel. For simplicity, the last two
parameters of the first two rows (MIDI Channel, Transmit Sounds, Gate/Hum Per
Sound, Aux Per Sound) are stored with each program, although they are global
parameters and the value stored (or received) within each program will be ignored. The
last six bytes of each program are spare and are reserved for future use. They should
be left unchanged. Currently, the last three bytes of these six are used to represent the

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