> On Jun 8, 2015, at 5:25 PM, Roland King <[email protected]> wrote: > > The difference between the tty device and the cu device is that ttys were > traditionally used to connect a terminal to, so opening a tty should block > until the device on the other end raises DTR (ie you turn it on). getty opens > tty devices and blocks in this way. The cu devices were designed for callups > where you needed to connect to say a modem first, then dial, and only when > the connection was established does DTR go high; so open doesn’t block. > Okay, that sounds like in general /dev/cu would almost always be called for (unless you’re doing actual terminal or modem work!) The way USB/serial devices seem to work on OS X is that they don’t even show up with a mount point unless they’re ready to communicate (perhaps at some level simulating DTR high?). In practice it hasn’t made any difference which I’ve used, cu or tty, but this info is good to know regardless. -Carl
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