mgrant@MIMSY.UMD.EDU.UUCP (03/08/87)
There are two types that I know of. There is something called "a bridge and a span", which, from what I can tell is basically a 1200 baud modem, one end on your mobil, the other in the switch at the center of the cell system. Then another regular 212 compatible modem dials out from there. This bridge and span stuff is supposed to be 212 compatible, but it's not error free if you connect straight to another 212 modem. Sorry, this is all I know about this product. I think MNP class 4 would work very well over cellular, provided that the MNP has it's timeout level set sufficiently high so as to not drop the line in long mutes, (greater than a few seconds), which sometimes occur in frindg areas. Why I say class 4 is that in fring areas you can get pops and clicks. True class 4 will try to ship data around this noise and try to create an optimum packet size. I have found that Microcom brand MNP modems time out much more quickly than some of their competitors, and hang up the line when the noise wasn't nearly as bad as it really was. This brand probebly wouldn't be good for this application. -Mike