smk@Mitre-Bedford@sri-unix (10/20/82)
Date: Sun Oct 17 10:04:57 1982 We have a MICOM Micro-600 port selector. After an intial hassle with not having the micom hang up the line (the fix is to cut the CTS wire -- which gets MICOM-4.1 to work perfectly), it works almost invisibly. Only >=3 breaks transmitted roughly 1 sec. apart ever disconnect the micom -- besides that, the micom is totaly transparent. We use it as the link for both cu (which I modified to support BOTH the micom and acu's) and uucp. If one machine is a UNIX machine, having cu will allow you to log into ANY other type of system hooked up to the micom. I needed to switch to the Berkeley line discipline, enable only flow control and tandem in CBREAK mode, and use the LITOUT ioctl. This puts you essentially in RAW mode for cu except that flow control is in effect. We need this so we can run cu at all the micom speeds, from 9600 to 110 (although why anyone would run at 110 is beyond me, but we have it). Also, to help reduce flow problems between computers, without the -s option, cu makes the micom link at the current speed of the local machine unless you explicitly override it. (we use cu w/o arguments to say use the micom, not the acu -- we don't have an acu yet, but our code for cu is unchanged from the distribution if you give it a telno.) We don't have poblems at all with the micom. I like it, because unlike other ways to link machine (or terminals to machines), is is transparent, i.e., it doesn't intercept certain control characters. It only catches break -- and if anything had to catch one character, I would want it to be break. Also, with the micom, you can have designations like dedicated/non-dedicated port/line, so there is alot of flexibility there. The designations apply to groups of 4 ports (Quads). --steve kramer