Panasonic KX-TC1468LBB, Service Manual

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16 CPU DATA (Base Unit)
16.1. IC3
Pin Port Name Label Init. I/O Description Remark
1 XOUT XOUT O 4MHz crystal oscillator
2 XIN XIN I 4MHz crystal oscillator
3 TEST TEST I Must be connected to Vss
4 P67 RSSIN I Carrier detect input (combo chip sigout) H: carrier present
5 P66 PAGE H I PAGE KEY L: KEY PRESSED
6 P65 DTMF5 H O recradle control, DTMF out5
7 P64 DTMF4 H O DTMF out4
8 P63 DTMF3 H O DTMF out3
9 P62 DTMF2 H O DTMF out2
10 P61 DTMF1 H O DTMF out1
11 P60 DTMF0 H O DTMF out0
12 P77 LEDP1 H O In-Use LED low: on
13 P76 LEDP2 H O Flash time option H: 300ms
14 VSS GND Ground
15 P75 TXDATA L O TX path data output
16 P74 TXRFPWR H O TX RF POWER CONTROL L: RF POWER OFF
17 P73 TXPWR H O TX power control L: TX power on
18 P72 RESERVED H O
19 P17 FLASHOPT L I Flash time option H: 600ms, L: 100ms
20 P16 COMCLK L O Combo chip clock, normal low output Pull low through 10k
21 P15 COMDATA L O Combo chip data, normal low output
22 P14 COMSTB L O Combo chip strobe, normal low output
23 P13 RXDATA H I RX path data input
24 P12 LSEIZE L O Line seize control H: seize line
25 P11 CHGDET H I charge detect L: charge
26 P10 RINGDET H I ring detect
27 RESET RESET I Power on reset pulse signal (w/charge reset)
28 VDD VDD Power supply (+5V)
16.2. Digital Security Coding System
Every time the handset is put on the charging cradle of base unit, a 16-bit digital security code is generated and exchanged
between base and handset. The security code is randomly selected amongst 65536 combinations. This is to comply with FCC
Part 15.214(d) requirement.
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KX-TC1468LBB