If you can convince me that all the device manufacturers will get this right such that all common operating systems will see this as a serial device (this isn't true for any ONE of the adapters currently available), then you are right. However, in my experience, the adapter that looks like a serial port to one operating system doesn't necessarily even work with another. While I have yet to see one which is universally interoperable, I also have yet to see an OS running on a USB-Only computer that doesn't work with at least one type of adapter.
Further, if I do choose to use a terminal server to control several devices, I don't know of anyone making USB terminal servers.
The bottom line is RS-232 is simple. No protocol required. No dependency on a protocol stack in the box, etc. For this particular purpose, in my opinion, the fewer dependencies, the better. USB introduces a significant number of dependencies. I don't mind dependencies on the operators laptop, because, the operator will usually make sure things work on his laptop on a regular basis. Building dependencies on the other side is an unnecessary complication.
Owen DeLong <owen@delong.com> writes:While it is true that builtin RS-232 on laptops is becoming rare, this isn't a good reason to eliminate the RS-232 requirement on equipment vendors. The reality is that I am willing to accept this on laptops because it is easy to find USB<-->Serial adapters that are well supported under all common laptop operating systems. On the other hand, it's not so common to find ways to support devices that have USB consoles with such vast compatibility.
I don't understand. There is no obvious reason why having a physical conversion device makes any difference. The console on the device can just speak the USB serial target protocol and all will look indistinguishable to the operating system.
-- Perry E. Metzger perry@piermont.com
-- If it wasn't crypto-signed, it probably didn't come from me.
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