On the M28 KSR, max typing speed was 100 per cent of printer speed. On keyboards directly connected to the perf/reperf (ASR in T mode, and KTR), I think max was about 150 percent of printer/reperf speed. Something like that. Not that I can come close for more than 4 characters in a row!
I don’t know about other machines.
Nick
A link would be welcome. What typing was required of Teletype operators? Somewhere I got the idea that direct connected keyboards were limited to half the speed of the printer (true or not?). Punches were not