NRD, CCITT working group 1968-1972, forerunner of Study Group VII, november 1971 they also talked about bit rates:

UK Post Office: 800bit/s, 3.2, 12.8 and 64kbit/s USA AT&T: 2.4, 4.8, 9.6, 48 and 56kbit/s (costumer data rates) French PTT: 800bit/s, 3.2, 12.8, 64kbit/s Switzerland proposed 160kbit/s

all of them seemed to agree in regard to multiplexing that 64bit/s should be standardized. While AT&T would use the same multiplexing techniques for national and international use, the british post office made a difference between national and international channels ...

In the long term it was expected that the networks provided by different countries would be fully synchronized and hence there would be no speed difference problem | GM/NRD No 77-E

on the other front there were still discussions where the digital data should come from - to make it a business, i guess. it was said "a keyboard operator can't type that much".