Speaking about ATM: the 48 byte payload was a standardization compromise between Europe and the US.
US companies had prototypes using 64 bytes, while European companies used 32 bytes. To avoid anyone giving a competitive advantage, they decided on a middle ground of 48.
There were trade-offs between 32 and 64 bytes as well: a 32 byte payload had a higher overhead than a 64 byte payload, but it had a shorter transmission time which made it easier to do voice echo cancellation.
Or so I was told many decades ago when I got introduced to ATM systems...
US companies had prototypes using 64 bytes, while European companies used 32 bytes. To avoid anyone giving a competitive advantage, they decided on a middle ground of 48.
There were trade-offs between 32 and 64 bytes as well: a 32 byte payload had a higher overhead than a 64 byte payload, but it had a shorter transmission time which made it easier to do voice echo cancellation.
Or so I was told many decades ago when I got introduced to ATM systems...