Radio Shack HTX-400 Service Manual

Also see for HTX-400: Owner's manual Owner's manual

Contents

16No. PIN NAME REMARKS DESCRIPTION ACTIVE1 VSS GROUND2 XOUT HIGH FREQUENCY CLOCK OUT3 XIN HIGH FREQUENCY CLOCK IN4 RESET RESET input5 P22(XTOUT) OPEN DRAIN N.C6 P21(XTIN) OPEN DRAIN CTCSS DEFAULT OPTION LOW:CTSS7 TEST Fixed to Low(GROUND)8 P20(INT5/STOP) OPEN DRAIN BUSY input (IN) High:Busy9 P40(INT3/TC3) TRI STATE PLL(LV2105) CLOCK (OUT)10 P41(PWM/PDO) TRI STATE ALERT TONE (PDO mode output) (OUT)11 P42(SCK1) TRI STATE PLL(LV2105) DATA (OUT)12 P43(SI1) TRI STATE PLL(LV2105) CE(CHIP ENABLE) (OUT)13 P44(SO1) TRI STATE ALIGNMENT MODE CONTROL ACTIVE “H”14 P45(SCK2) TRI STATE FX465 Serial Clock (OUT)15 P46(SI2) TRI STATE FX465 Serial Data (OUT)16 P47(SO2) TRI STATE FX465 Load Latch (OUT) High pulse17 P10(INT0) TRI STATE FX465 RX Tone Decode (IN) OK:”L”18 P11(INT1) TRI STATE TX Enable 1 (OUT) ENABLE:”L”19 P12(INT2/TC1) TRI STATE TX Enable 2 (OUT) ENABLE:”L”20 P13(DVO) TRI STATE EEPROM SERIAL DATA (IN/OUT)21 P14(PPG) TRI STATE EEPROM SERIAL CLOCK (OUT)22 P15(TC2) TRI STATE RX ENABLE (OUT) ENBALE:”L”23 P16 TRI STATE LAMP CONTROL (OUT) ON : “H”24 P17 TRI STATE AUDIO MUTE (OUT) MUTE : “H”25 P30 OPEN DRAIN KEY IN 1 (IN) ACTIVE:”H”26 P31 OPEN DRAIN KEY IN 2 (IN) ACTIVE:”H”27 P32 OPEN DRAIN KEY IN 4 (IN) ACTIVE:”H”28 P33 OPEN DRAIN KEY IN 8 (IN) ACTIVE:”H”29 P34 OPEN DRAIN *Reserved (IN)30 P50(AIN0) TRI STATE SIGNAL LEVEL (A/D) (IN) A/D31 P51(AIN1) TRI STATE BATTERY LEVEL (A/D) (IN) A/D32 P52(AIN2) TRI STATE KEY OUTPUT 1 (OUT) ACTIVE:”H”33 P53(AIN3) TRI STATE KEY OUTPUT 2 (OUT) ACTIVE:”H”34 P54(AIN4) TRI STATE PLL LOCK DETECTOR (IN) LOCK:”H”35 P55(AIN5) TRI STATE MONITOR KEY (IN) PUSH:”L”36 P56(AIN6) TRI STATE FUNCTION KEY (IN) PUSH:”L”37 P57(AIN7) TRI STATE MODEL SELECTOR (OUT)