Characteristics of MIDs
According to the MIDP 2.0 Specification [19], a MID should have these minimum hardware characteristics:
- Display
-
Screen size of 96-by-54 pixels
-
Display depth of 1 bit
-
Pixel shape (aspect ratio) of approximately 1:1
- Input – one-handed keyboard (ITU-T phone keypad), two-handed keyboard, (QWERTY keyboard), or touch screen
- Memory
-
kilobytes of nonvolatile memory for the MIDP components
-
8 kilobytes of nonvolatile memory for app-created persistent data
-
kilobytes of volatile memory for the Java runtime environment
- Networking
-
Two-way
-
Wireless
-
Possibly intermittent
-
Limited bandwidth
- Sound – ability to play tones, either via dedicated hardware, or via software algorithm
Example MIDs are mobile phones, two-way pagers, and wireless-enabled personal digital assistants (PDAs). Table 2.1 has some general system characteristics.
Table 2.1. Platform Characteristics
|
Characteristic
|
Mobile Phone
|
PDA
|
|
apps
|
Telephony, voice mail, address tutorial, web browser, text messaging
|
Address tutorial, to-do list, calendar, memo pad
|
|
Input device
|
Keypad buttons
|
Touch, stylus, QWERTY keyboard, IR
|
|
Mouse support
|
None
|
None
|
|
Keyboard support
|
Phone ITU-T keypad
|
Onscreen keyboard, QWERTY keyboard
|
|
Viewing distance
|
6 inches to 2 feet
|
1 to 2 feet
|
|
Display size
|
1-by-2 inches
|
2-by-2 inches
|
|
Screen resolution
|
A range that includes 96x54
|
A range that includes 160x160
|
|
Screen colors
|
Black and white through 16-bit color displays
|
Black and white through 16-bit color displays
|
|
Pixel density
|
to 102 or more DPI
|
to 102 or more DPI
|
|
Multiple screens
|
No
|
No
|
|
Audio input
|
Available
|
Available
|
|
Audio output
|
Speaker, headset
|
Speaker, headphones
|
|
Data bandwidth
|
14.4Kbps to 3Gbps
|
14.4Kbps to 3Gbps
|
|
Desktop synchronization
|
Available
|
Available
|
|
Bluetooth or serial network capabilities
|
Available
|
Available
|
|
Camera
|
Available
|
Available
|
|