Manual Switches
Electronic Control Pushbutton
LED, INCANDESCENT, OR NON-LIGHTED DISPLAY
FEATURES
Silver or gold contacts
Choice of rectangular or square
housings
Accepts one LED or incandescent
lamp
Printed wiring board or snap-in panel
mounting
Bezels and mounting clips, LEDs and
legended lenses can be furnished
installed or ordered separately
UL recognized, CSA certified
MML21 Series
PWB Mount
(Standard plunger)
Panel Mount
(Standard plunger)
Example: MML21KK3AAK
Electronic control pushbutton switch with
standard plunger; rectangular housing
(black); bezel (black); mounting clips on
long sides, PWB terminals; 1-pole, mo-
mentary action, silver contacts, black
plunger.
Example: MML21KK3AAKRSDR
As above, except furnished with red LED
and red lens installed.
MML21KK3AAHRSXX20
as above, leg-
ended.
PWB Mount
(One-piece plunger)
MML21 STANDARD PLUNGER SWITCHES ORDER GUIDE
Catalog listing codes for switch, less assembled display options
MML21K
Housing Type
MML21K
Rectangular Black Housing
MML21H
Square Black Housing
Mounting
Rectangular
A
No bezel (PWB
mounting)
K
Black bezel, mtg.
clip/long sides
K
Square
A
No bezel (PWB
mounting)
R
Black bezel
& mtg. clip
3
Terminals
3
Printed
Wiring
Board
2
Solder
Rectangular
Silver Contacts:
AA
1 pole,
mom. action
AB
1 pole,
alt. action
AC
2 pole,
mom. action
AD
2 pole,
alt. action
Gold Contacts:
BA
1 pole,
mom. action
BB
1 pole,
alt. action
BC
2 pole,
mom. action
BD
2 pole,
alt. action
AA
Circuitry/Action
(Each pole is double throw)
Square
Silver contacts:
AA
1-pole,
mom. action
AB
1-pole,
alt. action
Gold contacts
BA
1-pole,
mom. action
BB
1-pole,
alt. action
MML21 ONE PIECE LENS/PLUNGER SWITCHES ORDER GUIDE
Catalog listing codes for switch, less assembled display options
MML21H
Housing Type
MML21K
Rectangular Black Housing
MML21H
Square Black Housing
Mounting
Rectangular
A
No bezel (PWB
mounting)
K
Black bezel, mtg.
clip/long sides
K
Square
A
No bezel (PWB
Mounting)
R
Black bezel
& mtg. clip
3
Terminals
3
Printed
Wiring
Board
2
Solder
Rectangular
Silver Contacts:
AA
1 pole,
mom. action
AB
1 pole,
alt. action
AC
2 pole,
mom. action
AD
2 pole,
alt. action
Gold Contacts:
BA
1 pole,
mom. action
BB
1 pole,
alt. action
BC
2 pole,
mom. action
BD
2 pole,
alt. action
AA
Circuitry/Action
(Each pole is double throw)
Square
Silver contacts:
AA
1-pole,
mom. action
AB
1-pole,
alt. action
Gold contacts
BA
1-pole,
mom. action
BB
1-pole,
alt. action
72
Honeywell Sensing and Control 1-800-537-6945 USA
1-815-235-6847 International 1-800-737-3360 Canada
Manual Switches
Electronic Control Pushbutton Switches
MML21 Series
Electrical Data
Bezels
Strip and matrix mounting
PWB pin locations
page 69
page 84
page 83
page 91
Order display options assembled to switch by adding codes below
3
K
Plunger Type
K
W
Black
White
LED*
XX
RS
YS
GS
RS
Lens
XX
No Lens
DR
Legend
20
With Legend (Leave
Blank if no legend
needed
Use Legend Order Sheet
FO-74024 to cover each
catalog listing. (See page
80.)
No Led
4
Red
5
Yellow
5
Green
5
For LED Display
DR
Red
DY
Yellow
DG
Green
For Incandescent
or Unlighted Display
LR
Red
LY
Yellow
LG
Green
LW
White
LK
Black
CUSTOMER INSTALLATION:
LED
Incandescent Lamp
Manuals
1. Order LED and receptacle, page 84.
2. Installation instructions, page 85/87.
1. Order lamp/PWB receptacle or lamp/solder
receptacle, page 86.
2. Installation instructions, page 87.
Order display options assembled to switch by adding codes below
H
Button Color (One Piece Plunger)
LED*
RS
Legend
For LED Display
H
Red
L
Yellow
N
Green
For Incandescent or non-light display
R
Red
Y
Yellow
G
Green
Z
Black
XX
RS
YS
GS
No LED
4
Red
5
Yellow
5
Green
5
XX20
With Legend (Leave Blank if no
legend needed
Use Legend Order Sheet FO-74024 to
cover each catalog listing. (See page
81.)
*Notes:
1. When an LED is specified in a
rectangular
MML21 listing, MICRO SWITCH
will permanently install it in the housing.
2. MICRO SWITCH does
not
permanently install an LED in a
square
MML21
listing. To install an LED in a square housing, order a MML93L or MML93G
receptacle and a MML92 LED (see pages 86 and 88).
3. Include four digits (XXXX or XX DR) when a legend is required.
4. For square or rectangular only.
5. For rectangular only.
Honeywell Sensing and Control 1-800-537-6945 USA
1-815-235-6847 International 1-800-737-3360 Canada
73