Post by thread:[EE] CDC-ACM and Mac OS X network preferences dial

This is an interesting thread. It shows how difficult to convince Apple that there is an issue. Probably the answer from a prominent Linux USB developer finally wakes them up... The center of the issue is that often MCU developers use CDC-ACM for virtual serial port usage. And Apple insists popping up network preferences dialog for these device even though they are clearly not a modem. Start of the thread. http://lists.apple.com/archives/usb/2011//May/msg00051.html Then quite a few follow-ups in June. http://lists.apple.com/archives/usb/2011//Jun/index.html Apple claims that they are correct since CDC-ACM device are networking device. lists.apple.com/archives/usb/2011//Jun/msg00006.html "Since your device is declaring itself to be a networking device. That is what a CDC ACM device is. We are actually doing the right thing. In the past we had complaints because when a user plugs in a real CDC ACM device there was no way for the user to know where to go to configure the dial up connection. As far as I know the USB Device working group is not working on any standards for serial devices that are not related to networking. When you use a Standard device type for some other use we have no way of knowing this." Paul kind of gave up. http://lists.apple.com/archives/usb/2011//Jun/msg00009.html The discussions came back on September. http://lists.apple.com/archives/usb/2011//Sep/index.html Paul has more findings here. http://lists.apple.com/archives/usb/2011//Sep/msg00027.html Then I asked in the Linux usb mailing list and got the answer back to confirm his findings. Summary of the issue: lists.apple.com/archives/usb/2011//Sep/msg00031.html "The issue is the network preferences dialog popup appearing the first time a OS-X user first connects any USB Communication Class device. In the common case where the device is a modem or network interface, it's a real benefit. Modems in particular need manual user settings, so automatically prompting the user has excellent usability. But the usability is terrible in the increasingly common scenario where a non-modem device uses this protocol. Unexpected appearance of the network preferences can very falsely alarm users. At the least it's confusing or distracting." Apple finally seems to recognize that there is an issue. Hopefully they will fix in future version of Mac OS X. http://lists.apple.com/archives/usb/2011//Sep/msg00032.html -- Xiaofa

I have always thought a 'modem' is not necessarily able to accept AT commands. Moreover, not necessarily able to dial numbers or handle a PSTN line any other way. The word 'modem' is coming from MODulator-DEModulator, right? Aka modulating a digital signal on an analogue one and then demodulating it to digital at the other end - nothing more. Now we also have to define what 'network' is :-) But yes, 'network' is not equivalent to TCP/IP and not even necessarily need to meet the OSI model either, therefore popping up an IP settings is clearly silly. However, a 'network' also could mean any type of communication in between DCE and DTE including the hardware and software layer, so maybe Apple just need to redesign the network configuration window to popup the serial line settings instead (baud rate, stop bits, data bits etc) and only if you decide to put a PPP on top of it they need to bring up further settings. What do you think? Tamas On Tue, Sep 27, 2011 at 6:20 AM, Xiaofan Chen <spam_OUTxiaofancTakeThisOuTgmail.com> wrote: {Quote hidden}> This is an interesting thread. It shows how difficult to > convince Apple that there is an issue. Probably the > answer from a prominent Linux USB developer finally > wakes them up... > > The center of the issue is that often MCU developers use > CDC-ACM for virtual serial port usage. And Apple insists > popping up network preferences dialog for these device > even though they are clearly not a modem. > > Start of the thread. > http://lists.apple.com/archives/usb/2011//May/msg00051.html > > Then quite a few follow-ups in June. > http://lists.apple.com/archives/usb/2011//Jun/index.html > > Apple claims that they are correct since CDC-ACM device > are networking device. > lists.apple.com/archives/usb/2011//Jun/msg00006.html > "Since your device is declaring itself to be a networking device. > That is what a CDC ACM device is. We are actually doing the right thing. > In the past we had complaints because when a user plugs in a real > CDC ACM device there was no way for the user to know where to > go to configure the dial up connection. As far as I know the USB > Device working group is not working on any standards for serial devices > that are not related to networking. When you use a Standard device > type for some other use we have no way of knowing this." > > Paul kind of gave up. > http://lists.apple.com/archives/usb/2011//Jun/msg00009.html > > The discussions came back on September. > http://lists.apple.com/archives/usb/2011//Sep/index.html > > Paul has more findings here. > http://lists.apple.com/archives/usb/2011//Sep/msg00027.html > > Then I asked in the Linux usb mailing list and got the answer back > to confirm his findings. > > Summary of the issue: > lists.apple.com/archives/usb/2011//Sep/msg00031.html > "The issue is the network preferences dialog popup appearing the > first time a OS-X user first connects any USB Communication > Class device. > > In the common case where the device is a modem or network > interface, it's a real benefit. Modems in particular need manual > user settings, so automatically prompting the user has excellent > usability. > > But the usability is terrible in the increasingly common scenario > where a non-modem device uses this protocol. Unexpected > appearance of the network preferences can very falsely alarm > users. At the least it's confusing or distracting." > > Apple finally seems to recognize that there is an issue. Hopefully > they will fix in future version of Mac OS X. > http://lists.apple.com/archives/usb/2011//Sep/msg00032.html > > -- > Xiaofan >