Kenwood FM Transceiver TK-481 Service Manual

Also see for FM Transceiver TK-481: User manual Instruction manual Specifications Instruction manual Service manual

7TK-480/481OPERATING FEATURES4-5. Radio passwordWhen the password is set in the transceiver, user can notuse the transceiver unless enter the correct password.This code can be up to 6 digits from 0 to 9 and input withthe keypad or selector, and “S” key.4-6. Battery WarningThis transceiver has battery warning feature. If the lowvoltage is detected during transmission, the transceiverwarns it by flashing red “LED”.Then more low voltage is detected during transmission,the transceiver stops transmission and warns it by flashingred “LED” and beep.Please notice “standard” for the battery exchange,charging time by flashing red LED and beep.4-7. Minimum VolumeThe minimum volume is programmable (off (0) to 31).The transceiver remains the minimum volume level how-ever the mechanical volume position is set to zero.4-8. Call indicatorThe call indicator can be programmed for each group. Intrunked system, it can be set to respond to a selectable de-code ID or one of two fixed IDs, except block IDs. When acall is received with a selectable decode ID, the call indicatorflashes. When a call is received with a fixed ID, the call indi-cator lights continuously.On a conventional system, the call indicator can be pro-grammed to light for each QT or DQT code. It keeps flashingwhile a call is being received. It is turned off by pressing anyfront panel key.4-9. Free system ringbackThis feature is available only when a telephone intercon-nected ID code is selected. If a busy tone sounds when thePTT button is pressed, the transceiver enters this mode au-tomatically.When the PTT button is released, a beep sounds for400ms to indicate that the mode has been entered. If thescan is on, it is resumed (the “SCN” mark goes on). Whenany repeater becomes available, a ringing tone sounds andthis mode ends.The mode is terminated when the system, group, scan,PTT, key is changed.4-10. System searchThis feature can be programmed to automatically accessother programmed systems when the selected system can-not be accessed. If an intercept tone sounds when the PTTbutton is pressed after setting the mode, the transceiverhas entered the mode.If the group ID is a telephone interconnect ID, the trans-ceiver then attempts to access, in succession, other sys-tems that have a telephone interconnect ID in the revertgroup location. If the group ID is a dispatch ID, the trans-ceiver attempts to access other systems that have a dis-patch ID programmed in the revert group location.If there is no system to be accessed, an intercept tonesounds, the mode is terminated, and the transceiver returnsto the first system. If the access is successful, the mode isterminated, and the searched system becomes the new se-lected system (If during scanning, the scan stops).4-11. TranspondThis feature can be programmed to turn on and off foreach group. If the ID of the group for which transpond isenabled is received, two data messages (transmit ID andturn-off code) are automatically transmitted if the PTT but-ton is not pressed as a response within the time set (0 to300 seconds in 1-second increments). If the PTT button ispressed within the time, the transpond is not preformed.4-12. Transmit inhibitThe transceiver can be programmed with a transmit in-hibit block of ID codes. If an ID code within this block is de-coded the preset time before the PTT button is pressed,transmission is inhibited. The BUSY indicator lights and abusy tone sounds until the PTT button is released to indicatethat transmission is not possible (except clear-to talk mode).Transmission with the group for which the encode ID isnot set is inhibited, and the busy tone is output while thePTT button is held down, regardless of the clear-to -talk set-ting.4-13. Auto TELA telephone interconnect call can be made by simplypressing the key by assigning this feature to the key. Thisfeature accesses the TEL channel of the available systemautomatically.When the key is pressed, a queue tone is output, and the“AUTO TEL” appears on the alphanumeric display alongwith a flashing handset indicator ( ) to indicate that thismode has been entered. If the TEL ID is set for the revertsystem, the TEL channel of that system is accessed. If allTEL channels are busy, an attempt is made to access theTEL channels of another system in which the TEL ID codehas been programmed. It is repeated for 60 seconds untilthe access succeeds. If the access succeeds, a dial tonereturns from the repeater. If the key is pressed again whenthe queue tone is sounding, this mode is canceled.If the access fails after 60 seconds, a deny tone is outputand this mode is terminated. When the talk ends, the revertsystem/group returns. When the scan mode is effective, thescan resumes. The Auto TEL feature can be programmed toturn on or off for each system. ARQ modeIf affects Trunking mode only. Automatic Repeat Re-quest (ARQ) mode is a manner to minimize the air traffic ofdata communication. Also, it enables to occupy the trunkingrepeater channel for the data communication period. Data TX with QT/DQTWhether programmed QT/DQT is modulated or not witha data transmission except for Selcall. A radio unit can re-ceive a data message regardless of QT/DQT if the receivingunit is not scanning.