Kenwood TKR-750 Service Manual

Also see for TKR-750: Brochure & specs Service manual Function reference Service manual Instruction manual

10TKR-7506) Priority+TalkBack : The TKR-750 always reverts to thePriority channel. However, if a call is received on a chan-nel other than the Priority channel and PTT is pressedbefore scanning resumes, the transceiver “talks back”on the current receive channel.9. CW ID and MessageThe TKR-750 contains internal automatic station identifi-ers. The CW ID (Morse code) is set and transmitted on aper-channel basis. The CW ID is transmitted when the in-terval period is reached (TX Interval Time function), thechannel is changed (CW ID on Channel Change function) orCW ID Onfunction is executed. When CW ID is activated byany functions described above, it is actually sent after thetotal time of TX Delay Time (not applied to CW ID On func-tion) and CW Modulation Delay Time has expired. TX DelayTime is a period from CW ID is activated to the transmitter iskeyed.CW Modulation Delay is a period from the transmitter iskeyed to the CW ID tone is sent. The CW ID tone is routedto the Receive Audio (RA) port and a speaker if the Send CWID to RA function is set to Yes. The TKR-750 contains 8message banks for CW Message. CW Message 1 to 8 istransmitted on the current channel when the CW Message1 to 8 On function is activated, respectively.10. PTT PriorityA number of keying sources can be used to cause theTKR-750 to transmit.The transmit audio path is switched according to theirkeying sources and when PTTs is simultaneously activated,the transmit audio path related to the PTT with higher prior-ity is given priority. These are Local Microphone PTT, Exter-nal PTT, and Repeat PTT.11. Time Out TimerThe Time Out Timer function determines the period oftime users can continuously transmit. When the selectedperiod expires, the transmission is inhibited.12. Repeat Hold TimeThe Repeat Hold Time (hang timer) function is used toprevent the repeater from being repeatedly keyed andunkeyed in response to short message traffic. When a mo-bile transceiver unkeys, the repeater’s Hold Timer allowsthe repeater to continue transmitting for a brief period whilewaiting for a responding end user. If no valid QT/DQT isdetected within the Hold Timer period, the transmitter is al-lowed to unkey. This function determines the period of timethat the transmitter is allowed to remain keyed after the lossof a valid QT/DQT received signal.13. Take OverThe Take Over function is used to disable the externalwireline control of the repeater. When Take over function isenabled, the external AUX inputs and Outputs, transmit au-dio inputs and receive audio outputs, External PTT and Ex-ternal Monitor lines are disabled. All AUX Input functionsassigned to any AUX Input stay in their current state. How-ever External PTT and External Monitor switch to the “Off”state.14. Test ToneThe Test Tone is a single-frequency audio sine wave andis turned On and Off by toggling Test Tone On/Off functions.The transmitter can be modulated without a local micro-phone by using the test tone. When Test Tone On functionis executed and any PTT is activated, the TKR-750 transmitsthe test tone with mic mute and also routes the test tone toRA port.15. RF PowerThe TKR-750 is able to switch transmission output on aper-channel basis. When the TX High Power function is en-abled, the transmission output is set to high power.16. Fan ActionThe TKR-750 has a cooling fan. The Fan Action functiondetermines whether the fan is continuously operated or op-erates in response to high temperatures only.17. AUX Input and OutputThere are 6 programmable AUX I/O Ports 1~6 (pins20~25) and 3 programmable AUX Input Ports 1~3 (pins 4~6)on the rear 25 pin D-Sub connector (CONTROL I/O) and 5programmable AUX Output Ports 1~5 (pins 10, 11, 13~15)on the rear 15 pin TEST/SPKR connector.The 6 programmable AUX I/O pins are primarily intendedfor remote control interfaces. Each AUX I/O Port can be setfor AUX Input, AUX Output, remote Channel Select or MultiTable Select types. The AUX Input Port can be set executea single input function or a set of up to three functions whenthe port is activated. If the port type for an AUX I/O Ports1~6 is set for “AUX Input”, it will also appear AUX Inputwindow for function programming. The input logic is fixedas active Low.The AUX Output Port can be set execute a single outputfunction. If the port type for an AUX I/O Ports 1~6 is set for“AUX Output”, it will also appear AUX Output window forfunction programming. The output logic of AUX Output canbe set as either active High or active Low by the Logic Typefunction. Active High outputs a High (5V) when the pro-grammed condition becomes valid, active Low outputs aLow (0V) when the condition becomes valid.OPERATING FEATURES