random findings by wt8008
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  • Samsung Galaxy S 4G Notes

    Posted on January 9th, 2012 wt8008 No comments

    Unlock: The Galaxy S can be sim unlocked as the community found that the unlock code was stored in plain text within a particular file.

    Rooting: giving you root access to the phone.

    • Use SuperOneClick to root the phone: http://shortfuse.org/
    • You will need USB drives. I believe I used the ones which were included with the Samsung Mini Kies software

    ROM flashing

    • Instructions for installing ROM with CWM (clockwork recovery): http://forum.xda-developers.com/showthread.php?t=1215748
    • The procedure flashes a new ROM with CWM installed and using CWM to put on a new ROM.
    • Note: Recovery mode and Download mode are different. Recovery mode (up/down/power buttons pressed). Download mode (up/down buttons pressed while inserting USB cable).
    • CWM allows to install new roms/files from the SDcard while in recovery mode.

    AT&T 3G Support for T-mobile Galaxy S 4G:

    • Phone officially supports T-mobile 1700/2100 MHz UMTS Band IV (AWS), and also over seas Band I (2100)
    • Phone also supports AT&T 1900 MHz UMTS Band II (PCS) from testing with a SIM. Historically, T-mobile uses the 1900 MHz band for only 2G coverage, but has been expanding 3G services on this band. This is the cause of the resent reports of 3G data available on AT&T’s iPhones.
    • AT&T also uses 850 MHz UMTS Band V, not supported on this phone. In some areas AT&T only uses 850 MHz for 3G coverage. On my trip from San Jose to Las Vegas, I found that when there is 3G coverage, almost everywhere also had 1900 MHz coverage. The lower frequency of 850 MHz does penetrate buildings better, which can make a difference in some areas.
  • Porting AT&T Landline Phone to Google Voice

    Posted on October 4th, 2011 wt8008 2 comments

    In my previous post, I explained how I purchased a Obi110 for use with Google Voice. I am porting my landline phone to Google Voice for use with my Obi110 and some features. I have to first port the landline to an intermediate cell phone provider (T-mobile), since Google Voice only supports porting in from cell phone providers. (See the link in the reference section for detailed instructions.)

    Currently, the AT&T landline bill is about $28 after all fees and taxes. The landline itself is about $20 and the remaining $8 consists of taxes and fees.

    Timeline

    This is the timeline of events for porting.

    • Thurs 09/22/2011 08:28 PM – Order Placed for prepaid SIM for $7.57
    • Fri 9/23/2011 – Shipped
    • 9/24 – 9/25 Weekend
    • Tue 9/27/2011 Afternoon – Arrived
    • Weds 9/28/2011 Afternoon – T-mobile Prepaid Online Activation, did not take long, does ask for a cell phone IMEI. I’m sure it doesn’t matter what you put in there.
    • Weds 9/28/2011 12:45pm – Call T-mobile Porting Department at 1-877-789-3106, right after activating. The call took about 8 minutes and I received a reference number to the porting request. It was stated that it could require 3 to 10 business days to port, but it may be faster.
    • Thurs 9/29/2011 06:45 PM – T-mobile asked to call them regarding the port. The porting department did not have my prepaid number on file and needed to know it so they can replace my cell number. My landline number was also released by AT&T to allow for the porting to begin. T-mobile activated and said that calls will slowly go to T-mobile over the course of 2 to 24 hours. For a period of time calls went to either the landline or the cellphone.
    • Fri 9/30/2011 8:30 AM – Begin port to Google Voice. The prepaid account number is the landline number with area code. Also dial tone for the landline was lost.
    • Fri 9/30/2011 12:38 PM – Email from Google regarding incorrect PIN. Resubmitted Prepaid PIN.
    • Sat 10/1/2011 8:30 AM – Email from Google notifying port completion.
    • Sat 10/1/2011 10:00 AM – Tested phone service to verify functionality.
    • Verify with AT&T that the landline has been canceled.

    It required two days to finish the port from the evening of 9/29, all day on 9/30, until the morning of 10/1. I did not try to receive calls on the prepaid phone during the port to Google Voice. Callers were directly placed into T-mobile voice mail. Make sure to check the voice mail box before the port is complete. Press * to interrupt the greeting and then the last four digits of the landline number as the voice mail pin.

    Costs

    It will require 2.5 months to break even assuming free calls, which is currently true, see the summary table below.

    Obihai 110 $42.99
    T-mobile Prepaid $7.57
    Google Voice Port $20
    Total $70.56
    Time for ROI 2.5 months

    It is unknown if free calls will remain beyond 2011.

    References

  • Experience with Obihai Obi110 and Google Voice

    Posted on September 22nd, 2011 wt8008 No comments

    Edit: Google will be shutting down XMPP for Google Voice in May 2014, rendering the Obihai box less useful. I will need to find a new system before then.

    I brought an Obihai Obi110 not too long ago. By connecting a normal PSTN phone to the FXS port and to the internet to the ethernet port, the Obi110 allows for VOIP on your old landline phone. The Obi110 supports up to two standard SIP providers or Google Voice. The Obi110 also has a FXO port so you can also connect your current landline to it. You can receive calls from any of the two VOIP providers or your current landline. (See block diagram.)

    Currently I setup the device to dial out over Google Voice. The second SIP provider is Onesuite used for international dialing purposes. For receiving calls, I am currently using my old landline number. Later, I will port this into a VOIP provider or to Google Voice (via T-mobile). I am going to wait and see what Google Voice does with Google Chat initiated calls, if it remains free or the per minute charges. Call out via Google Voice and receiving calls via the landline works as expected with excellent voice quality. Proper QoS settings may be needed to reduce jitter. (UDP destination port 5060 for SIP and TCP destination port 5222 for Google Talk.)

    E911

    Another issue is E911, I believe most setup with a separate VOIP provider which has this feature. For serious setups, a UPS power backup is also needed. Besides the broadband mode, router, the Obi110 itself, any wireless phones also need backup power.

    Features

    Some features which I now can have access to are caller id, voicemail indicator, and 3-way calling/call forwarding. Google Voice providers free caller id (number only), which is an expensive feature with my landline provider. With new voicemails on Google Voice, the Obi110 can signal the phone to light up the voice mail indicator. Google Voice with the Obi110 allows for 3-way calling and call forwarding from the phone by flashing the phone and dialing the destination number. Any of these features are costly extras if I used them with my landline service.

    Obihai also provides a nice web based site to setup, configure the device and status monitoring. Perhaps, you can use this to configure, setup, and maintain remote clients for family. You can setup speed dials for frequently used contacts.

    The Obi Attendant allows you to call your Obihai device and make phone calls from it by matching caller id. An application is to allow us to access our international VOIP provider via our cell phones.

    Others also setup an Asterisk PBX to do a more elaborate setup or dialing plan, but it is not necessary for me.

    Goal

    With AT&T raising landline rates and fees (disguised as taxes), it would be great to cut off the $20/mo landline bill. Although there will be some short-term hardware costs and number porting fees, it will require 3 to 6 months to become net positive.

  • VPS Trim Down Memory Usage

    Posted on August 8th, 2011 wt8008 No comments

    This post is meant to be a list of todo items when setting up a VPS with low memory. It is not designed to be accurate or complete, just some notes and observations.

    • lighttpd – web server replacement for apache, configure home directory sites and additional domains.
    • mysql – disable innodb, which is the cause of most of the memory usage, and use conservative configurations to save memory. Newer versions of mysql do not have bdb option, so it is not necessary to disable it.
    • dropbear – ssh server to replace openssh, add as start up service. Each ssh connection spawns a new process, so the memory savings adds up.
    • php – limit to 1 process and a small handful of threads. I use 1 process and 4 children.
    • bind9 – disable this process, it is not necessary
    • postfix – install a smaller mail server
  • List of RSS Feeds on my Google Reader

    Posted on July 19th, 2011 wt8008 No comments

    Edit: As of 7/2/2013 Google Reader has been shutdown. I have migrated to Feedly for now.

    What is on your Google Reader? I have way too many subscriptions on my Google Reader and cannot rigorously read each item. Google Reader is web-based RSS feed aggregation, for those who have not heard of RSS, you are missing out. If you subscribe to a particular website feeds, then when the site pushes out a new update, it will show up as a new item in Google Reader. Now, if you like to visit many sites for to read new articles, you can visit Google Reader in place of visiting each site individually. It is a time saver and waster.

    I originally used Google Reader to put in blogs and sites that I rarely visit, since there were a large number of sites that I was semi-interested in that did not require a daily visit. Now it is my main source for reading blog and news posts, since it is convenient to only visit Google Reader. Here are some of the sites that I currently subscribe to.

    Electronics/Technology/Industry:

    • IEEE Spectrum Online – IEEE members should already know about this, bringing news related to the broad discipline of electrical engineering.
    • Electronic Design – industry news, magazine
    • EE Times – industry news, magazine
    • Electronics Blog – showcases links to other places of people’s DIY projects or to introduce new parts
    • SparkFun Electronics – DIY/hobbyist electronics site for parts, started up a few years ago from University of Colorado students. I follow the feed on the home page for new product announcements and user’s projects.
    • bunnie’s blog – the monthly Name that Ware series is always a brain teaser, where a cropped out photo is shown for readers to guess what it is from

    Technology/Linux:

    • Slashdot – “News for Nerds. Stuff that Matters”, I don’t need to explain this one. With a broad audience, sometimes news from here is overlapped from the other sites.
    • Omg! Ubuntu! – Ubuntu Linux related posts, usually orientated towards users for customization
    • Terminally Incoherent – random posts about movies, games, IT stories
    • Rickipedia – slow to update, more information on industry used Linux distros

    Comics:

    • xkcd – A webcomic of romance, sarcasm, math, and language. A must read, if you can figure the comic out (hint: see the xkcd forums).

    Financial:

    • The Finance Buff – the blog authors various observations and investigations to items involving money and finance
    • Money:GTL – no update in half a year, not sure if the author is going to keep up with the postings

    Others:

    • mustangdaily.net – Cal Poly student newspaper
    • Cal Coast News – local news for California Central Coast communities
    • Serious Eats – food based blog with many interesting topics beyond just recipes such as food policy, news, and laboratory experiments
    • Incorrect Basketball Knowledge – Podcasts on sports that I mean to listen to one day, but not have yet

    These links are directly to the sites, you will have to dig around and look for the orange RSS icon for each site to get the feed URL.

    I do have a few more, but the list is getting too long. The amount of effort it put in to read each one varies due to the volume of new posts everyday.

  • LG Incite

    Posted on October 31st, 2009 wt8008 No comments

    In August, my family got some new cell phones, the LG Incite and Samsung Eternity. As you can see it is currently November, so this is old news.

    The phone only comes in silver, and it is a touchscreen based phone. The touchscreen itself is average, but should be more responsive. When comparing with the Eternity, it is obvious that the Incite is not as responsive, and both phones use a resistive touchscreen. There is no D-pad on the phone, so the touchscreen is the main way to navigate through the interface, although there is a small scroll wheel on the side. Other buttons include a camera button and lock button, but the buttons can be customized to open other programs or perform other actions. The phone also includes a 3.5mm standard headphone jack, useful for listening to phone calls or music, without any special plugs. Before, I didn’t like having my iPod and cell phone together in my pocket, but since I always carry my combined mp3 with me, I listen to Podcasts daily. (More TWiT listeners ;)) Of course, the iPod interface is not comparable with my phone, but I don’t find it worth the extra effort to carry it for a few minutes of music/podcast appreciation on the short walk to class. The camera is 3 megapixels, but from CNet sample photos, the camera on the Eternity results in pictures with better brightness, especially in low light situations. There is also a stylus, but there is no proper place for it on the phone. The stylus just ties onto the phone, and hangs off of it. I feel that the stylus gets in the way when it is hanging there, so I didn’t put mines on. The phone includes internal A-GPS that works well with the Google Maps, especially on satellite view! I disabled the “A” part of A-GPS, because assisted GPS uses the cellular towards to give an initial position, while the GPS hunts and locks to the satellites. This method works by having the towards send data to your phone, about 7KB each time. Data? That is a no-go for me, since it is $2/MB, so 7KB rounds up to $2.

    I was able to get the phone for free without a dataplan. The price and the lack of dataplan requirement was the reason why I purchased this phone. There are registry hacks to disable MediaNET, as smartphones can use lots of data by itself, by auto-connecting to the Internet and check email or update weather conditions. The ability to disable built-in data, including auto-connecting to 3G/EDGE was also an important consideration before I got the phone.

    From the factory the phone runs Windows Mobile 6.1, which is not finger friendly at all, once you move away from LG’s interface into Windows Mobile land, the tiny buttons and scroll bars are very difficult to work with, and impossible if you were on-the-go. The leaked Windows Mobile 6.5 versions out there are way better, they definitively do not require a stylus. With WinMo 6.1, it would be handy to have one around, but with 6.5, you can toss it out. The phone has limited memory, so multitasking can slow down the phone a lot. (Although, I can also consider myself lucky for being able to multitask.) From time to time, I need to verify sure programs are actually exited, and not still running in the background, as lack of memory is not good, especially for running Internet browsers. Sometimes, I will get out of memory errors, when opening new programs, and if there are memory leaks, then a reboot is in order.

    Google Sync for Windows Mobile via Google’s exchange server is also a convenient feature that syncs my contacts, email, and calendar onto my phone. Activesync automatically keeps my phone up to date via WiFi. Calendar with alarm reminds sometimes can come in handy. Syncing contacts allows for backing up, and handling only one address book. It can also support push email, but nzane2k noted that it was slow to push. When I move around WiFi hotspots, I sometimes need to manually restart the syncing process.

    I have tried to take a few photos, but I didn’t really try hard at all.

    LG Incite box and free Bluetooth headset

    LG Incite box and free Bluetooth headset

    Where is the phone

    Where is the phone

    Comes with a USB cable, Samsung users don't get one!

    Comes with a USB cable, Samsung users don't get one!

  • To Grandma

    Posted on October 31st, 2009 wt8008 No comments

    May you rest peacefully.

    October 29, 2009

  • Tomato Firmware Hostname

    Posted on July 29th, 2009 wt8008 No comments

    I always wanted to access my router via its hostname instead of typing the router IP in. This works fine in Linux, but for some reason Windows resolves hostnames different. I checked in windows with nslookup, and it can resolve my router name, but in Firefox or IE it doesn’t work. I had the same problem when using dd-wrt.

    In the Basic->Identification section, I randomly added a domain name of home, and now windows can resolve the router hostname and router.home, also points to my router. For past routers I used, I typically leave this field empty, as the documentation says it is provided by my ISP. This solution doesn’t require massive editing of config files on the router or editing host files.

    The computers can resolve themselves just fine either via the router DNS, Samba, or Avahi. I am not sure which one is doing the work.

  • Chinese Characters in Flash

    Posted on July 17th, 2009 wt8008 No comments

    With flash, Chinese (font) characters show up as boxes instead of the character itself. To remedy the issue

     $ sudo rm /etc/fonts/conf.d/69-language-selector-zh-cn.conf

    I don’t like the shipped configuration default for Ubuntu CN anymore. Don’t worry this is only removing a symbolic link.

    Create a new file /etc/fonts/conf.d/63-wqy-zenhei.conf and populate it with

    <?xml version="1.0"?>
    <!DOCTYPE fontconfig SYSTEM "fonts.dtd">
    <fontconfig>
    <alias>
    <family>sans-serif</family>
    <prefer>
    <family>WenQuanYi Zen Hei</family>
    </prefer>
    </alias>
    <alias>
    <family>monospace</family>
    <prefer>
    <family>WenQuanYi Zen Hei</family>
    </prefer>
    </alias>
    </fontconfig>

    This files adds the WenQuanYi Zen Hei font to the sans-serif and monospace font families.

    Next, in the 30-cjk-aliases.conf file accept the WenQuanYi Zen Hei font as acceptable mappings to Windows fonts such as SimSum and MingLiu. Make sure that the font is first, as the system will pick the font by ordering. A sample snippet of affected areas

    <!-- Aliases for Simplified Chinese Windows fonts -->
    <alias>
    <family>SimSun</family>
    <family>NSimSun</family>
    <family>SimSun-18030</family>
    <family>NSimSun-18030</family>
    <family>宋体</family>
    <family>AR MingtiM GB</family>
    <accept><family>WenQuanYi Zen Hei</family></accept>
    <accept><family>AR PL UMing CN</family></accept>
    <accept><family>AR PL ShanHeiSun Uni</family></accept>
    </alias>
    <!-- Aliases for Traditional Chinese Windows fonts -->
    <alias>
    <family>MingLiU</family>
    <family>細明體</family>
    <family>PMingLiU</family>
    <family>新細明體</family>
    <family>AR MingtiM BIG-5</family>
    <accept><family>WenQuanYi Zen Hei</family></accept>
    <accept><family>AR PL UMing TW</family></accept>
    <accept><family>AR PL ShanHeiSun Uni</family></accept>
    </alias>
    <alias>
    <family>標楷體</family>
    <accept><family>WenQuanYi Zen Hei</family></accept>
    <accept><family>AR PL UKai TW</family></accept>
    <accept><family>AR PL ZenKai Uni</family></accept>
    </alias>
    <!-- Alias for HKSCS -->
    <alias>
    <family>Ming (for ISO10646)</family>
    <accept><family>WenQuanYi Zen Hei</family></accept>
    <accept><family>AR PL UMing HK</family></accept>
    <accept><family>AR PL ShanHeiSun Uni</family></accept>
    </alias>

    Now, Chinese charaters in font work correctly without editing 49-sansserif.conf to map unknown fonts to sans instead of sans-serif. The solution which others have suggested created an issue with the font of a buddy on pidgin.

  • Algorithm on Studying for Finals

    Posted on December 8th, 2008 wt8008 No comments
    void study(void)
    {
        study();
    }
    

    That is it, it works quite well sometimes. 😉 It never ends, until you blow up.