Timothy Murphy wrote: > Mikkel L. Ellertson wrote: > >> If you are using the CUPS web administration, look at the "Device >> URI:" line. One should be a USB device, and one an >> ippd://<address>:631/<something> - the ipp:// one should be the >> default on all but the machine with the printer attached. > > Dear Mikkel, > > Are you suggesting one should use the ipp:// URI rather than http:// ? > I always use the http one, on the grounds that I've heard of http . > Is there really any difference? > I assume one is not really using http, just the protocol. > Yes, I am for the printer URI. http: is HyperText Transfer Protocol - ipp: is Internet Printing Protocol (If I have the acronyms correct.) In any case, it is one of the printing protocols, and it is designed for network printers. On the other hand, http: is not designed to be a printer protocol. To a large extent, it is replacing the older lpr protocol. When you are accessing the CUPS web interface, you would still use http:// to get the human-readable interface. But your printer should not be doing this. > It's a pity CUPS gives an inordinately long URI for USB printers. > Well, part of the reason for this is to make sure you are printing to the correct printer, even if it is plugged into a different port, or in a different order. It also makes sure you are talking to the correct function on multi-function devices. I don't know it there are USB printers that support different print queues, but I imagine that would also affect the URI. I know it does on ipp printers and print servers. (The last <something> in the URI is normally the print queue.) Mikkel -- Do not meddle in the affairs of dragons, for thou art crunchy and taste good with Ketchup!
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