GENERAL DESCRIPTION
The W91F820N is a series of tone/pulse switchable telephone dialers with 13-flash memory, keytone, hold, lock, and handfree dialing control features. These chips are fabricated using Winbond's high performance CMOS technology and thus offer good performance in low-voltage, low-power operations.

FEATURES
• Tone/pulse switchable dialer
• Two by 32 digits redial and save memory
• Three by 32 digits one-touch direct repertory flash memory
• Ten by 32 digits one-touch direct or two-touch indirect repertory flash memory
• The read-write times: 104
• Pulse-to-tone (*/T) keypad for long distance call operation
• Chain dialing
• Uses 5 ´ 5 keyboard
• Easy operation with redial, flash, pause, and */T keypads
• Pause, P®T (pulse-to-tone) can be stored as a digit in memory
• Dialing rate:10 ppS or 20 pps by mask option
• Minimum tone output duration: 93 mS
• Minimum intertone pause: 93 mS
• Pause time: 3.6 sec.
• Flash break time (73 mS, 100 mS, 300 mS, or 600 mS) selectable by keypad; pause time is 1.0 S
• Make/break ratio (2:3 or 1:2) selectable by MODE pin
• Mute key for speech network mute
• No key will be accepted except the "HOLD" key when in the Hold mode
• Key tone output for valid keypad entry recognition
• On-chip power-on reset
• Uses 3.579545 MHz crystal or ceramic resonator
• 20-pin 300 mil, or 22-pin 400 mil dual-in-line plastic package