Re: pci-to-parallel vs usb-to-parallel?
On Mon, Aug 18, 2008 at 09:00:06AM -0700, Bob McGowan wrote:
> Tzafrir Cohen wrote:
>> On Fri, Aug 15, 2008 at 10:33:50AM -0700, Bob McGowan wrote:
>>> Mike Fontenot wrote:
>>>> My new PC doesn't have a parallel port on the back (or anywhere else),
>>>> and I need one for my HP1200 B/W laser printer. I've seen inexpensive
>>>> PCI cards that have one or two parallel ports, and also some cables that
>>>> convert between USB and parallel.
>>
>
> --<Deleted on purpose>--
>
>>> Speed over USB will be limited to the PP port speed at max but could
>>> be impacted by other devices on the USB bus, if there are any.
>>
>> Speed? Even USB1.1 is about the same speed of a parallel port (probably
>> faster). And with USB2 you have nothing to worry about with the speed.
>>
>
> At first reading, I thought you misunderstood my point. On second
> reading, I think maybe I misunderstand yours. So, to see if I grok
> what you said...
>
> Since USB 2 can deliver data much faster than the parallel device can
> consume it, even if you have multiple devices on a single USB bus, data
> will probably get to the printer fast enough for it to receive data at
> its highest design rate.
>
> But, for USB less than 2.0, assuming the USB speed is about equal to the
> parallel bus speed, multiple devices could impact data flow enough to
> cause the printer to have to wait on occasion.
>
> According to Wikipedia's IEEE 1284 spec. parallel port speed for EPP/ECP
> is 2/2.5 MBits/s, while USB 1.x is 1.5/12 MBits.
>
> So, unless the USB is constrained for some reason to the 1.5 MBits/s low
> speed, USB data rates should be high enough to keep the printer data
> transfer rate at it maximum.
>
> Am I close to understanding correctly?
So you don't have a USB 2.0 port on your system?
There's also the strange option of buying a PCI card of a USB
controller. Those are quite common and cheap, but then you lose the edge
mentioned in:
>
>>> If it were me, I'd factor in the cost, as well. If they were close,
>>> I'd probably choose the USB interface path, mostly due to not
>>> needing to open the chassis to implement it.
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