DCMT and CCMT are insert designations, with C being a 80deg diamond and D being a 55deg diamond.
This link is a good guide for what all the letters mean - https://www.carbidedepot.com/formulas-insert-d.htm
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SCLCR is a toolholder designation, that takes CC_T inserts.
Carbide depot also has this page explaining the individual digits - https://www.carbidedepot.com/formulas-th-d.htm however the additional sizes on that chart are for imperial not metric.