USB Serial CDMA Mobile WWAN CCL PPP PL2303

Hello all,

I have an internet connection issue or issues. It seems this is a complicated issue because there are so many layers involved.

Hardware:

iMac9,1

2, IOGear USB Extension cables (powered)

Mobile phone manufacturer supplied USB-Serial Cable.

Huawei branded CDMA 2000 1x RTT mobile phone with Qualcomm modem and Prolific PL2303 USB-Serial Bridge.

R-UIM card for local ISP in Nepal (United Telecom Limited)

Software:

Mac OS 10.6.8

I have tried a few different ways to make the connection and getting a connection isn't necessarily the issue.

First I tried to use the Prolific PL2303 kext. It's widely known you have to add the devices Vendor ID and Product ID to the info.plist file for the driver to load the device at boot time. But, apparently we don't need that third-party kext because Apple has built in support for Huawei as evidenced in three existing kext files: WWANSupport, WWANSupport1, and AppleUSBMergeNub (that lives as a plugin inside IOUSBFamily.kext). Problem was that the phone was not being recognized by the system even though the Vendor ID was a match. Any guesses why?

I figured a way for the device to be recognized via the CellPhoneHelper.kext. Huawei is not listed but duplicating the 'Qualcomm CDMA Technologies MSM (KPC680)' IOKitPersonality and then reconfiguring it to match my Huawei device by changing the Vendor and Product IDs worked perfectly. Once I cleared the system cache files and rebooted the phone was recognized immediately as a WWAN device and I could set it up in Network Preferences. Using the Generic and CDMA settings for the modem script I am able to connect. That's where the fun bit ends.

The connection gets wonky. It randomly leaves me in limbo, seemingly connected but not able to receive any data. If I 'disconnect' using the WWAN menu, it shows me as being disconnected but actually I am not, the phone is still be connected to the tower. If I open up a serial program I can see that the phone is still sending data. The only way for me to end the connection is to unplug the USB cable. Then I can 'Connect' again and everything pretty much repeats. I will have a decent connection and then at some random point I will loose it and be unable to disconnect from the tower. This is a stationary setup; not roaming.

One thing I have noticed is that the tower will give me a different WAN address randomly. Maybe this is the issue! While connected I will see in 'ppp log' that I am being logged out and logged in again and then I am given a different LAN address and WAN address. Sometimes I will get an error, 'Could Not Authenticate" and I will be disconnected. Sometimes it appears to work seamlessly. This all happens automatically. I am not sure from which side this is being initiated, my modem or software or the ISP's?

I have poked around but don't really know what I am looking for. Is this an issue with the CDMA.ccl, or an issue with PPP, or is it a USB IOKit issue, or a kext issue? Who knows.

When typing 'sudo dmesg' in Terminal I get something that seems odd to me, but might be completely normal.

AppleWWANSupport1: Version number - 2.0, Input buffers 16, Output buffers 4

AppleWWANSupport1: Version number - 2.0, Input buffers 4, Output buffers 2

I took note of the Input and Output buffers in the CellPhoneHelper.kext info.plist and they are 16 and 4 for my device. I don't know why 4 and 2 immediately override those. I don't see anything in AppleWWANSupport1 that has 4 and 2 set for buffers. Could this be the issue, i.e. the connection freezing because the buffers get full? Or could it be because the mobile phone is using two channels for the modem, /dev/cu.wwan and /dev/cu.wwanCNTL and that is normal??

I took a look at the CDMA.ccl modem script. I am not a modem script designer but I noticed that 'C' is set twice in the same init, &C1&C2. I am not exactly sure why that would be, any ideas?? Track remote DCD (&C1); Unix compatible DCD control (&C2). What about 'hsreset'? Not sure but I guess the Prolific PL2303 chip handles the serial port flow control options? The literature is a bit out of date on this.

So, lots of questions and no answer so far. A bit too complicated as there are so many layers working together and this is not a supported configuration. I do see a lot of people asking similar questions but mostly it's on different systems, like Linux, etc.. and with different hardware.

Would love to hear from someone with experience, a programmer or someone familiar with Apple's IOKit and modem inits.

Regards,

John