看見TTY在用Tru Sim，就去它的網上看了一下，http://www.truphone.com/us/ 好象在美國可以免費接收短信
充值後多長時間作廢網上沒注明，於是給客戶服務打電話。被告知：永遠不作廢，但有一個前提：私人賬號不能連續六個月沒有動靜。
non usage of the sim for 6 months it will automatically be deactivated and the remaining balance will be forfeited. An account maintenance fee of $2 or 3 GBP will be observed. Also what you can do is atleast try to send an sms once in a while so that it will reflect on our end that you are still using the sim lets say in a span of 3 months.
聽起來令人難以置信：$30買個卡，含$15充值，並跟來一個電話號碼。你就有永遠免費接收短信的功能了。在美國費用如下：
Call landlines cost per minute: $ 0.09
Call mobiles cost per minute: $ 0.09
Receive call/text cost per minute: $ FREE
Send a text cost per message: $ 0.09
Data per MB: $ 0.09
這麽看來，除了免費接收短信這個功能，其它都比不上最近壇裏網友sailfish發現的Lycamobile：通話費$0.05/分鍾，數據$0.06/MB，短信$0.04/個，用手機查留言不收費！
How much does it cost to access the voicemail? Your Lycamobile Voicemail service has been automatically activated. To access your voicemail from your Lycamobile in the US dial 121 (or 91#). Calls to access the voicemail are absolutely free. Does Lycamobile charge taxes on my order? All charges are inclusive of tax. However, there may be required sales and similar taxes that are required by the state and are charged by the retailer where you purchased your Lycamobile products. There may also be various federal and state fees that Lycamobile must collect or that Lycamobile must pay as part of regulatory requirements that Lycamobile may pass on to its customers.
Lycamobile 的用戶有人反映常有垃圾短信，這個比較頭痛，每收到一條垃圾短信要花費$0.04。他們的客戶服務也沒有好的解決辦法，不過似乎可以關閉短信功能：
How can I stop receiving unwanted texts or SPAM? When you receive a text from a company you have not given your number to, this is called SPAM. Unfortunately, Lycamobile is unable to prevent you from receiving these unwanted messages, unless you want to ban all text messaging. These companies have sophisticated ways of obtaining cell phone numbers. One way to avoid SPAM is to be careful about what sites you give your cell number to.
如此看來，兩個服務都有最好，用Trusim接收短信，用Lycamobile接/打電話。估計用那些雙SIM卡的手機做這個最合適了！
拿到了Lycamobile 的SIM卡，試驗時發現個問題
Lycamobile 的留言是自動開啟的。如果有人打你的手機並留言，要按分鍾計時收費，留幾分鍾算幾分鍾，不管你的手機是否是關閉的。這樣一來，前邊說過的查手機留言不收費就沒有什麽優勢了，因為在被留言的時候已經收過費了。
比較煩這個，我從來不願意為廣告垃圾留言付費。幸好他們有政策，就是隻要你給客服打電話要求，就可以關閉留言。當然，關閉留言後，誰都無法給你留言。我的解決辦法是，把號碼捆綁到股哥語言（Google Voice），這樣留言就用股哥語言免費查了。
如此看來，關閉短信和留言服務後，你就有一個$0.05/分鍾的純語音電話。
