Tethering the Samsung SCH-r450 on MetroPCS
by VXO
Introduction
MetroPCS is a flat-rate CDMA wireless carrier with service in some larger metropolitan areas throughout the United States.
MetroPCS service requires no contract, and uses customer-owned handsets. The service plans include unlimited use of local and long distance voice services. Text messaging, picture messaging, voicemail, and wireless web access are available on higher plan levels, or are available separately. The plans range from $30 to $50 per month.
The phones available on MetroPCS currently range from the more basic "candybar" handset at $80 to a BlackBerry Curve at $450. Various MetroPCS phones are plentiful on eBay and other sources.
The Samsung SCH-r450
Before the BlackBerry Curve was offered, the r450 Messager was MetroPCS's only offering with a full keyboard.
The top of the phone slides sideways, exposing the full QWERTY keyboard below. The display will flip to landscape when you turn the phone. Strangely, the Binary Runtime Environment for Wireless (BREW) environment and browser only operate with the slide open. The BREW implementation on the older Kyocera Strobe would operate on the external or internal LCDs.
The r450 has a 1xRTT connection, BREW software environment, 1280x960 pixel camera, Bluetooth audio and object exchange profiles, GPS, MicroSD socket, music player, and built-in Openwave web browser.
BREW applications available for the phone include Metro411 (a V-Enable Mobile411 directory assistance app), Mail@Metro (an e-mail client), Loopt, and a Mobile IM client.
BitPim does not recognize the phone yet. It doesn't appear to support the proper AT commands to kick it into BREW mode, and won't talk to it as "Generic CDMA phone" or anything. To get files on and off of the phone, use USB storage or Bluetooth object exchange.
External sockets are provided for a mono or stereo headset with 2.5 mm plug, and a port for a USB data cable, charger, or other compatible accessories.
The USB cable is provided in the box. No accompanying software is supplied. In the menu under "Settings -> Phone Settings -> PC Connection", you can enable or disable USB mass storage. If you have USB storage enabled, plugging in the phone will put it into USB mass storage mode. Nothing else functions while it's in USB storage mode, though the phone will charge. When you're done, unmount the volume and press the soft key for "Done" to go back to normal operation.
The phone will charge on any powered USB 1 or 2 port. No driver is required for charging. This handset is not nerfed like the Razr!
USB CDC ACM class modem support is present on the phone, but it's disabled out of the box. Once this is enabled, if you have the wireless web feature enabled on your account, you can hook the phone up to your computer and use it as a wireless data connection.
Press OK to get into the menu, then 9#. The phone will ask for a code, which is 587846. You'll see a number of otherwise hidden options, including DUN mode. Scroll down to DUN mode and turn it on, then power cycle the phone, just for good luck and fortune. Connect the USB cable and you should get a USB CDC ACM class modem device!
On Linux, this will be /dev/ttyACM0. On Mac OS X 10.5, it will show up as /dev/tty.usbmodem***. On 10.4 it comes up as something different.
ls /dev | grep -i modem should show it. The output of dmesg should show something like this:
If you use ZTerm or Minicom to connect to the serial device, you should be able to get the usual modem responses.AT should yield OK, and ATI should yield a bunch of info:
If USB storage mode is enabled, you will probably also see an "initDevice failed message." This is harmless, and the device will be recognized once you hit Done on the phone. Open "System Preferences" and go to "Network". A box should pop up saying it found a new device, "Samsung CDMA Technologies". Choose it in the "Show:" dropdown box, and you'll get a modem settings page.
Set the account name to your phone number, 3055551234@mymetropcs.com, and the password to mymetropcs. The telephone number is #777. Go to the "Modem" tab, and select "Generic -> Generic Dialup Device" for the model. On 10.4, selecting "Verizon Support (PC 5220)" seems to work well.
If the phone likes the resulting init string and settings, you should be able to make the system dial it, and it'll almost immediately show an IP address in the 10.* range. You're in. Now you can immediately connect to anything, anywhere, on port 443.
MetroPCS blocks anything on ports other than 443. If you want web access on 80, you're going to need to go through a proxy. They provide a web proxy at wap.metropcs.com port 3128. It doesn't appear to need a username/password. You can enter this in the "Proxies" tab under the network configuration. Entering it as a web HTTP proxy works. I haven't been able to get other applications to connect through it properly if entered as a SOCKS proxy, so it may just be web only.
The wap.metropcs.com proxy is a strange one. It's got a captive portal, which is that same lovely semi-useless orange and blue "Downloads" page you get on the phone when you start the browser. After about a minute of inactivity, you get thrown back to that page with the next HTTP request. If you hit that page from a normal web browser, you get a 404 thrown off from Apache Coccoon.
The wap.metropcs.com proxy also tends to be pretty slow, so you may want to find another proxy somewhere that listens on 443. A test run at speedtest.net through the Metro proxy showed 112 kbit/sec down, and 64 kbit/sec up, with a ping response of 999 msec. This isn't exactly EV-DO, but it isn't too bad either. I've found that FreeNX runs well over the connection to a SSH server on port 443 to connect up with a remote X11 desktop.
Windows users can also do this with a driver included in Samsung PC Studio. PC Studio won't do anything with the phone itself, but it'll drop the proper driver on the system for the "Samsung CDMA Technologies" device to use it as a modem.
Unfortunately, the phone software does not support Bluetooth dial-up, so you're going to need the cable. The cable appears to just be a mechanical cable with no converters or anything.
For more information on the hidden features of the Samsung SCH-r450, check out the Samsung r450 Hacker's Manual, available on handsonforums.com.
For best results on the MetroPCS network, keep your phone's Preferred Roaming List (PRL) up to date. Dial *228, wait for it to ask you what you're calling about, hit 2 and enjoy the wonderful little beat it plays. You should see "Programming in progress", "SPC Unlocked OK!", and "PRL Download OK!" appear on the bottom of the screen in a tiny font. When it finishes, it will reboot.
Enjoy, and happy hacking.
Shouts out to: Robert, who first introduced me to MetroPCS; Nikola Tesla and Guglielmo Marconi, who pioneered wireless transmission and telegraphy so many years ago, bringing us easy access to information today.