The Standard Horizon HX370 is a marine VHF radio sold explicitly to operate on both the maritime 2-metre band between 156 MHz to 163 MHz, plus the wider VHF Land Mobile Radio (LMR) range either side of this. It's small, incredibly solid, and very heavy, being partly cased in metal. It has a small physical volume compared to its mass, which means it sinks like a brick if dropped in the water, unlike the HX851 which floats! There radio also has ATIS transmit for usage within the European RAINWAT inland waterways area. For amateur radio repeater use, the HX370 has CTCSS.
The radio seems to have has an 16kB EEPROM. There are three channel banks which are bitmask programmable to enable/hide channels from a hardcoded à la carte menu selection of 240 marine VHF frequecy combinations. In addition there are 40 fully-programmable LMR channels.
The serial port is via the microphone jack port on the top and has the same pinout as the rest of the Yaesu range. Screw it all the way down to get the contacts to align.
The access sequence to place the HX370S in programming mode to is Down+H/L+MEM+Power. If you're wondering how to logistically perform this, place the radio across-ways in front of you, antenna pointing at your left-hand palm. Using the middle three fingers on your right hand, press-and-hold the three bottom buttons, grasp and twist the Power rotary knob with the thumb and index-finger of your left hand. The display will then show Edt
,The LMR channel bank has 40 slots, each of which has RX Frequency, TX Frequency, 12.5kHz/25kHz, Low Power, Power Up, Scan, Channel Name, Channel Tag, plus RX CTCSS, RX DCS, TX CTCSS, RX DCS. The latter being what you need for Amateur Radio 2m-repeater usage.