Since people have asked me on detailed information about commands, i hereby provide the IT.txt source with its commands. Its more detailed about some commands, than the modplug helpfile.

3) The third column contains the volume or panning of the note.
To toggle between entry of volumes and panning, press '`'

Volumes.
0 is the softest (ie. nothing) and 64 (decimal!) is the loudest.
If no volume is specified, then the default volume for the sample
is used. (Note that effects *CANNOT* raise the volume above 64)

The volume scale works linearly - ie. one note played at a
volume of 64 will be the same 'loudness' as 4 of the same note,
one played at a volume of 10, another at a volume of 30,
another at a volume of 20 and another at a volume of 4.
(10+30+20+4 = 64)
But if you have a choice, always go for the single note (it
will require less processing (occupy less channels), and also
sound better in quality, due to roundings that occur in processing
softer volumes).

Panning.
Panning controls appear in a different colour to the volume
controls. For panning in this column, 0 represents far left, and
64 represents far right. If you have an Xxx effect at the same
time, the Xxx will take precedence over this column.

It is more efficient filesize-wise to use a panning control in
this column rather than in the effect column.

Volume, Panning & Effect??
OK. So you want to do something tricky. Well, it's possible to
get all 3 of these how you want with a little meddling with
the channel volume control - just place one before the row with
an appropriate value (remember that the range is 0->40 HEX) such
that the channel volume scales the default volume to the desired
value.... What I mean is that if you want to play a note at volume
32, pan 48, with vibrato H81, then you can do the following:

ฆจจจ จจ จจ M20ฆ - Set channel volume to HALF.
ฆC-4 01 48 H81ฆ - The 48 is a pan command - this assumes that
the default volume for sample/instrument 1
is 64.

Volume Column Effects
In IT208 and higher, some extra functions are available in the
volume column. These allow you to slide the volume up/down and
pitch up/down, just like the final column effects. If you aren't
familiar with the rest of the editor, leave this section out for
now and come back after you have become acquainted to column
(4) of the editor - the effects column.

Volume column effects are selected by pressing A-H in the first
column of the effects.

Ax = fine volume slide up by x
Bx = fine volume slide down by x
Cx = volume slide up by x
Dx = volume slide down by x
Ex = pitch slide down by x
Fx = pitch slide up by x
Gx = portamento to note with speed x
Hx = vibrato with depth x

In all cases, if x is 0, then the effect memory is used (as
explained in (4)

The memory for Ax/Bx/Cx/Dx are shared, as is the memory for
Ex/Fx.

4) The final column contains effect data. For those of you who are
just starting, I would advise you to leave this section until
later, when you have already dabbled with entering notes, and
want some special features. It's easy to get caught up with all
these special features and you can 'overdo' the effects.
And it will sound absolutely pathetic.

Trust me, I know - I've done it Smile

Effects are entered by typing 'a'-'z', then a hex value
(see later for an explanation of hex numbers) as the final two
entries. The effects allow you to a wide variety of functions
that are otherwise impossible to obtain.

Due to the repetitive nature of some effects, there is a
'memory' so that instead of typing:

จจจ จจ จจ G12 It is easier to จจจ จจ จจ G12
จจจ จจ จจ G12 use: จจจ จจ จจ G00
จจจ จจ จจ G12 จจจ จจ จจ G00
จจจ จจ จจ G12 จจจ จจ จจ G00
จจจ จจ จจ G12 จจจ จจ จจ G00
จจจ จจ จจ G12 จจจ จจ จจ G00
จจจ จจ จจ G12 จจจ จจ จจ G00

The following effects 'memorise' their previous values:
(D/K/L), (E/F/G), (HU), I, J, N, O, S, T, W

Note: Bracketed commands share the same 'memory' value. So

จจจ จจ จจ E12 can be written as: จจจ จจ จจ E12
จจจ จจ จจ F12 จจจ จจ จจ F00
จจจ จจ จจ E12 จจจ จจ จจ E00
จจจ จจ จจ F12 จจจ จจ จจ F00
C-4 01 จจ G12 C-4 01 จจ G00

Commands H and U are linked even more closely.
If you use H00 or U00, then the previous vibrato, no matter
whether it was set with Hxx or Uxx will be used. So:

จจจ จจ จจ H81 Is the same as: จจจ จจ จจ H81
จจจ จจ จจ U00 จจจ จจ จจ H81
จจจ จจ จจ U83 จจจ จจ จจ U83
จจจ จจ จจ U00 จจจ จจ จจ U83
จจจ จจ จจ H00 จจจ จจ จจ U83

Hex Numbers
Note: Impulse Tracker works ENTIRELY with decimal numbers
EXCEPT for the effects column.

Instead of using a decimal system (ie. base 10), it is more
natural for the computer to work with hexadecimal (often
abbreviated to simply 'Hex') - numbers which operate in base
16. The first 9 numbers in hex are denoted by '1' to '9' and
the next 6 are denoted by 'A' to 'F'. So if you count in hex,
it will be as follows: (0), 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B,
C, D, E, F, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 1A, 1B,
1C, 1D, 1E, 1F, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 2A etc.

To convert a hex number to decimal, multiply the 'tens' column
by 16 and add the value of the second column. ie. 32 Hex =
3*16+2 = 50 decimal. 2A hex = 2*16+10 = 42. (because A = 10)
The maximum number that you can represent with two Hex digits
is FF = 255 decimal.

Hope that this makes SOME sense Smile

Effects.

Axx Set Speed.

I prefer to think of this command as "Set Frames per Row".
Normally, the tracker operates at around 50 frames a
second. If the rows were played at this speed, then a huge
amount of space would be required to enter the pattern data.
Instead, setting the 'speed' of the song will cause the
tracker to wait on the current row for 'xx' frames. Hence,
setting the speed at 50 (decimal = 32hex) will cause each
row to last about a second - quite a long time! The default
is A06. The initial speed can be set in the variables
screen on F12.

If two Axx commands are given in the same row, then the
command in the higher channel (by number) will take effect.

Bxx Jump to order.

Causes the song to jump to order xx (hex). This is often
used to create looping songs.

If two Bxx commands are given, then the command in the
higher channel will take effect.

Cxx Break to row.

The Command Cxx signifies the end of the current pattern,
and also that the next pattern should be played from row
xx (hex)

If two Cxx commands are given... you know Smile

D0x Volume slide down

The volume slide down command causes the volume of the
note to be reduced by x for each frame after (for that
row). ie. If you have a note at volume 64, with command
D01 and speed A06, then the final volume will be 64-5=59.
A note at volume 32 with command D02 at speed A05 will
result in a volume of 24.

For greater S3M compatibility, D0F will cause the volume
to drop by 15 EVERY frame, instead of just off-note frames.

Here's a full frame-by-frame description which should provide
greater understanding:

At 'speed' 4:
C-4 01 .. D04

What this does is:
Frame 1: Plays C-4 with instrument 1
Frame 2: Lowers the volume by 4
Frame 3: Lowers the volume by 4
Frame 4: Lowers the volume by 4

The next frame will be controlled by the next row of
information.

Dx0 Volume slide up.

Operates exactly the same way as D0x, but slides the
volume up by 'x'. Volumes cannot exceed 64 (checked
and limited internally).

For greater S3M compatibility, DF0 will cause the volume
to rise by 15 EVERY frame, instead of just off-note frames.

DFx Fine volume slide down.

Takes the volume down by x at the start of the row.

DxF Fine volume slide up.

Takes the volume up by x at the start of the row.

Exx Pitch slide down

The pitch will slide down with speed xx (hex). In linear
frequency mode, a pitch slide down by a particular value
will always cause the same "pitch interval" - this does
not occur in Amiga frequency mode. Valid ranges for xx
are between 0 and 0DFh (as > 0E0h will be interpreted as
fine slides)

EFx Fine pitch slide down

Slides the pitch down by x at the start of the row.

EEx Extra fine pitch slide down

Same as EFx, but 4 times finer. (ie. EE4 is equivalent to
EF1)

Fxx Pitch Slide up
FFx Fine Pitch slide up
FEx Extra fine pitch slide up

Operates in the same manner as the Exx commands, but
slides the pitch up. If the pitch gets 'too high', then
the channel is turned off.

Gxx Portamento to note.

This command requires 2 parameters: A note to slide to
and a speed. Example:

C-4 01 จจ .00
G-4 01 จจ G08
จจจ จจ จจ G00
จจจ จจ จจ G00

This will cause the note C-4 to slide to G-4 with speed 8.

You *CAN* change the sample that the note is sliding to.
It is a good idea to make sure that the C5Speed of the
samples is similar, if you want to try this! The new sample
will play from it's beginning.

Hxy Vibrato with speed x, depth y

Causes the frequency to osciallte with depth 'y' at speed
'x' which causes an interesting effect. Don't get carried
away with it though! If you specify EITHER x or y as 0, then
the previous value will be used.

Ixy Tremor with ontime x, offtime y.

Causes the volume of the instrument to remain normal for
x frames, then sets the volume to 0 for y frames.

Jxy Arpeggio with halftones x, y.

This causes the note to quickly cycle through three notes -
the note playing, a note x halftones above, and a note y
halftones above. This causes an effect similar to old
C-64 chords.

Example: C-4 01 จจ J47 will cause the notes C-4, E-4 and
G-4 to be cycled.

Kxx Dual command: Vibrato + Dxx (Volume slide)

Note: The vibrato could have been set with either Hxx or
Uxx

Lxx Dual Command: G00 + Dxx (Portamento to and Volume slide)

Mxx Set channel volume

Each channel has a volume range from 0->40h. The lower
the value, the softer the notes in the channel. This
command is convenient for making 'echoes'... you won't have
to modify the echoing channel from the original, except
for placing a M20 at the top of it!

Values greater than 40h are ignored at playtime.

N0x, Nx0, NFx, NxF Slide channel volume commands

These commands work in the same manner as the slide
volume commands, but operate on the channel volume,
rather than directly on the note volume.

Oxx Set sample offset.

This will cause a sample to be played from offset yxx00h.
This is useful to skip past the first part of a sample
which may have a loud hit, or to start a speech sample
half way through.

If you specify a value PAST the end of a sample, then the
command is ignored.

The "y" part of yxx00h is set with command "SAy"

Example:
... .. .. SA5
C-4 01 .. O10

This will play note C-4, instrument 1 at offset 51000hex

Note to programmers: Oxx for 16-bit samples will move
to the xx00h*2 position in the sample - ie. the 'xx00th'
sample.

P0x, Px0, PFx, PxF Slide panning commands.

These work in the same maner as the slide volume
commands, but operate on the channel panning. P0x slides
the panning right, while Px0 slides the panning left.

Qxy Retriggers a note after y frames with volume modifier x.

This will cause a sample to be replayed from it's
beginning after every y frames. 'x' can be any of the
following:

Value Effect on volume each retrig.
0 No change
1 -1
2 -2
3 -4
4 -8
5 -16
6 *2/3
7 *1/2
8 No change
9 +1
A +2
B +4
C +8
D +16
E *3/2
F *2

Rxy Tremelo with speed x, depth y

This command acts similarly to the vibrato command, but
affects the note volume, instead of the pitch. If you specify
EITHER x or y as 0, then the previous value will be used.

S3x Sets vibrato waveform to x
S4x Sets tremelo waveform to x
S5x Sets panbrello waveform to x

Values for x: 0 = sine wave
1 = square wave
2 = Ramp down
3 = Random!

S70 Past note cut
S71 Past note off
S72 Past note fade

With the loss of 1-1 correspondence of editing channels
to internal playing channels, these commands provide
control over notes that have already been played by a
channel.

Example:
Consider the following situation, where instrument
1, notes C-4 & D-4 map to a looped sample, and the
New Note Action is set to continue.

C-4 01 64 .จจ
D-4 01 64 .จจ
E-4 01 64 .จจ <--- Use S70 here!

Ordinarily, control would be lost over C-4 and D-4, but
using command S70 at the point indicated, the notes C-4
and D-4 would be stopped immediately when the note E-4
plays.

Similarly, note off commands and Fadeout commands can
also be issued.

Note: You *MUST* be in instrument mode for these
to have any significance.

S6x Pattern delay for x ticks.

S73 Set NNA to note cut
S74 Set NNA to continue
S75 Set NNA to note off
S76 Set NNA to note fade

These options allow you to override the default NNA for a
particular NOTE (ie. it does not affect the instrument)
See section 2.5 for an explanation of NNAs.

Note: You *MUST* be in instrument mode for these to have
any effect.

S77 Turn Volume envelope off.

Stops the processing of the volume envelope. This is for the
times that you don't want to use the volume envelope that
you've created.

S78 Turn volume envelope on.

Sometimes, you'll decide that it's better not to use the
volume envelope for most cases, but you may just want to
use it a few times - this is the command that lets you
do that!

Note: You *MUST* be in instrument mode for this to work.

S8x Set panning position

Set panning position, S80 is leftmost, S8F is rightmost.
This is an obsolete command, provided only for ST3
compatibility. Use command Xxx instead.

S91 Set surround sound!

For those of you who are lucky enough to have a dolby
surround sound decoder (myself not included - so if ya
wanna send me something.....), this *should* cause the
sound to come from the surround speaker. This is a
pseudo-panning command, and issuing either Xxx or S8x
will cause the surround sound to be reset.

If you try and play Surround Sound on a GUS, Interwave
or AWE32, it will be played as a central pan.

SAy Set high-offset. Check Oxx for an example.

SB0 Set loopback point
SBx Loop x times.

This pattern space-saving feature will cause the pattern
to be looped x times back to the last SB0. Note that you
can only loop within the pattern! Also, each channel has
it's own loop-back information... so you HAVE to have the
SB0 and SBx in the same channel for it to operate.

SCx Note cut after x frames

This will cause a note to be immediately stopped after x
frames. It is similar to issuing a "^^^" in the note column,
just that it has a finer control over timing.

SDx Note delay for x frames

Actually, this command works like "interpretation" delay
for x frames. Any data - note, sample/instrument or volume
in the channel will not be interpreted until x frames into
the row.

SEx Pattern delay for x rows

This will cause a "pause" on the row for effectively x rows
longer.

Note that if TWO pattern delay commands are issued, then
the only the command in the higher channel will be considered.

Txx Set tempo to xx

Valid ranges are between 20h and 0FFh. The higher the
value, the faster the playback. This essentially
determines the time length of each frame, by the following formulas:
Frames per minute = 24*Tempo
equivalently:
Frames per second = 0.4*Tempo

T0x Tempo slide down
T1x Tempo slide up

Tempo slides up and down are used to smoothly modify the
speed of the song. The tempo is modified by ฑx every
non-row frame.

Uxy Fine vibrato with speed x, depth y

Same as vibrato, but 4 times finer in depth.

Vxx Set Global volume

Valid ranges are between 0 and 80h. All notes playing are
affected by this change.
Values greater than 80h are ignored at playtime.

W0x, Wx0, WFx, WxF Slide global volume

Similar to the Dxx commands, but operate on the global
volume. Useful when fading out songs.

Xxx Set panning position

Sets the panning position anywhere from left to right (X00
is left, XFF is right).

Yxy Panbrello with speed x, depth y.

What the hell is panbrello? Well, it's a word that I coined
late one night after a friend suggested that there should
be a random pan position command. I decided.. why not - I'll
make the vibrato/tremelo equivalent of panning! And so you
have here, 'panbrello.' What this does is instead of
oscillating frequency (pitch) or volume, it oscillates the
panning position about the 'set' panning position for a
channel. This is for you techno freaks out there who want
another function to stuff around with! Smile

The random pan position can be achieved by setting the
waveform to 3 (ie. a S53 command). In this case *ONLY*, the
speed actually is interpreted as a delay in frames before
another random value is found. so S14 will be a very QUICK
panbrello, and S44 will be a slower panbrello. With any
other waveform, the higher the value for x, the faster the
panbrello, like vibrato and tremelo. If you don't know what
I'm talking about, check out the stereo-indicators on the
info page (don't forget that you have to be in stereo mode!)

If you specify EITHER x or y as 0, then the previous value
will be used.

Copied from the original document IT.TXT that was written by Jeffrey Lim aka Pulse