lauren@RAND-UNIX.ARPA (10/24/85)
While I can't comment on the transparency or lack of it within MNP (I don't have enough info) I do know that one aspect of the advertising of these modems could really cause problems for naive users. Often the manufacturers imply that since the MNP protocol is error correcting, you don't have to worry about any other error-correcting software. This is almost always NOT the case. The fact that the data path between modems may be error free says nothing about lost data between the modem and the CPU, especially on small or busy systems, where loss can occur at bps rates as low as 2400. Usually the modem makers offer flow control like ^S/^Q (which definitely isn't transparent and isn't sufficient to avoid losing some data on many systems) to try reduce this problem. But it isn't enough, and many (most) systems don't support alternate flow control systems in any case. So while those modems may theoretically protect "part" of the path, they do not provide the full range of control and coordination that their advertising frequently implies. A surprise for the unwary. --Lauren--