[ih] Arpanet line speed

[dave.walden.family at gmail.com]

The satellite links to Europe and Hawaii by 1973 were maybe 9.6kbs.   By that time (or 1975) the IMP code knew about four different line speeds (as I remember) -- 9.6, 50, 300 (I think) and something else (I can look it up in the code). The IMP had to know the line speeds as part of deciding if a link was up or down based on how long it was between receiving instances of interIMP traffic.