The legacy packet network frequency known as “Net105” is reference to the lower sideband frequency 14.105 LSB with 300 baud AX/FX.25 tone pairs configured at 1600hz and 1800hz respectively- 1700hz being the center frequency.
Some stations run multiple modes as well as additional packet ’channels’ for BBS interlinks etc, these can be found only on the USB frequency as the multi modes such as VARA500, ARDOP500 and Robust Packet are sideband sensitive and sit at a fixed center frequency of 1500hz.
AX.300 AFSK tones are sideband-insensitive and will work compatibly with stations on opposite sidebands at slightly different dial frequencies, so the USB dial frequency of 14.1022 has been selected to keep backwards compatibility with Net105 as well as provide an additional allocation to handle BBS traffic separately to help increase throughput.
The equivalent TNC tone pair for Net105 on the Upper Side Band frequency is 1000hz and 1200hz, 1100hz being the center frequency, the additional AX/FX.25 300 baud allocation pair is at 1900hz and 2100hz (2000hz center frequency).
The multimodes run at a fixed center frequency at 1500hz, with the packet channels described sitting on either side.
The various new-skool multimodes run at a fixed center frequency at 1500hz, with the packet channels described sitting on either side, depicted in this screenshot:
You may want to try running QtSoundModem as it helps to visualise the spectrum with a waterfall.