The wireless data transmission standard Bluetooth can transfer up to 723kbps which means speeds of up to 72kbytes/sec are possible. However, not one of my handhelds acheived speeds of more than 10kb. The Palm OS connection settings limit the speed to 115200bps. I have already wondered about this for quite some time. I was at the vienniese Siemens Embedded Day today. There were some electronic soccer robots-and the operator talked to somebody else about wireless data transmission. My presence led to the discussion of bluetooth speeds in mobile devices. This is what the operator had to say:
Most bluetooth chips use the HID protocol for communication-and usually connect to the host CPU via a serial link(USB dongles use-nomen est omen-USB). These serial links usually cannot acheive much more than 115200bps. Thus, most stacks are designed for only this speed. If the link is faster, the stack slows it down.
Seems quite plausible to me, because: Many people underestimate the importance of the stack. Some Freescale Semiconductor Microcontrollers include an ethernet stack. The Freescale engineer urged the participants of the seminar to evaluate the different stacks, as some could MORE THAN DOUBLE data throughput. Now as if this isn’t performance impact!
BTW, the presentator informed the listeners that neither symbian nor PPC devices are faster. They use Xscale CPUs too, so they won’t have a faster link. So, we can at least rest assured that the competition doesn’t surf faster!
I am-as always-looking forward to some interesting discussion!
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Same for usb dongles, i can only get 54KB/s on my laptop to host computer. Too slow and weak.
With the use of protocols the bandwidth gets smaller. I don’t think it is useful.