Telecom is for very high grade boards, usually having a lot of IC chips, gold pin connectors, etc. and little junk weight from large capacitors, steel, unpopulated areas (or not populated with valuable materials). I’m not sure how to best describe low telecom, but I would say the gap between peripheral and high telecom (not including mobo and other specific boards), or like very high grade peripheral.
https://boardsort.com/telecom.htmlPeripheral is better than mid grade but not quite motherboard grade. High peripheral is close to low telecom but not quite. Low peripheral is a bit higher than mid grade but not as high as high peripheral.
https://boardsort.com/peripheral.htmlBelow that is midgrade, which are boards with very few IC chips, junk weight from large connectors with few gold pins, lots of large capacitors, has metal and/or plastic parts that could be trimmed/removed, has heavy transformers or inductors, etc.
Low grade currently pays the same as mid grade, however, it is most brown or tan PCBs with the least value.
Gold cap chip board are boards with at least one gold cap chip on them.