The idea of developing a universal ADTRX_UR4QBP_V2 board came to me immediately when I decided to try connecting my ACER TravelMate 2410 laptop to the ADTRX_UR4QBP board. Reception worked fine on the built-in AC`97 sound card, RX/TX switching worked via a USB-COM adapter, but I still couldn’t get it to transmit… As you know, most, and I would say all, laptops have sound cards with combined linear and microphone inputs in one connector. I decided to add another signal relay with two groups of contacts to the circuit to switch the sound card input either to the NE5532P op amp output in reception mode or to the microphone in transmission mode. The board works with the KGKSDR program. The circuit diagram of the board Fig. 1 has practically not changed compared to the ADTRX_UR4QBP board, I only added one relay and a stereo jack.
Fig.1
The ADTRX_UR4QBP_V2 board connection diagram Fig. 2 is very simple, but still requires explanation. Fig. 2  The COM port connecting cable is soldered according to the diagram, on the computer side, a blocking capacitor is soldered to pins 7 and 5 of the connector. Without it, some boards refused to transmit. The microphone is connected to the "TO MIC” connector of the board, if the sound card has a combined input (there is no pink connector on the sound card). The audio cables connecting the board and the sound card of the computer or laptop must be made of separately shielded cores (each core in its own shield). The 3.5 mm stereo jack of the cable to the computer input is soldered in parallel, and the line output cable is soldered the other way around. This is due to the peculiarity of the board layout, solder as I wrote above. There may be problems with mismatching reception and transmission, if you confuse it, reception will be mirrored with transmission. In the KGKSDR program settings, do not enable IQ signal inversion (the checkbox in Option> Tranceiver> Swap I/Q in & out must be unchecked), if enabled, the panorama will flip and the frequency scale will not correspond to reality. Connect the "TO LINE OUT PC” connector of the board to the linear output of the sound card with an audio cable, connect stereo phones or active computer speakers or some kind of low-frequency amplifier to the "TO PHONE” connector. It is convenient to use an "audio twin” with one 3.5 mm "dad” and two 3.5 mm "females”. Stereo phones are connected to one of the "females”, and active speakers to the other, we want to listen to the phones, we want to listen to the speakers, having connected the latter to the network with the power button. We connect the pedal to the "TX ON” and "GND” connectors according to the diagram, supply power to "+ 12V” and ”GND”. Connect the "+TX” and "+RX” connectors according to the diagram. Connect the antenna or DFT to the "RF IN/OUT” board input. The heterodyne signal with an amplitude of 200...300 mV is fed to the "LO IN” connector, the average frequency for the board operation is calculated using the formula Flo in = Favg. x 4, where Flo in is the frequency at the "LO IN” input, Favg. is the average frequency of the range (the same is set in the KGKSDR program). Board and connections diagram in SPlane 6 format, printed circuit board in Sprint Layout 5 format — DOWNLOADPhoto of finished board — 
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