sim800 模式切换

SIM：订户标识模块或订户标识模块 (SIM: Subscriber Identity Module or Subscriber Identification Module)

SIM is an abbreviation of a Subscriber Identity Module or Subscriber Identification Module. SIM is a portable chip and an integrated circuit that firmly, stably and securely stores the international mobile subscriber identity (IMSI). It is a smart memory card that creates a possibility to make a phone call across the world where the availability of the user's network is stable.

SIM是订户身份模块或订户身份模块的缩写 。 SIM是一种便携式芯片和一种集成电路，可以牢固，稳定且安全地存储国际移动用户身份(IMSI)。 它是一种智能存储卡，可以在稳定用户网络可用性的世界范围内拨打电话。

SIM is commonly used in smartphones that function and manage on the GSM network. It is movable and a user can use it with any supporting smartphone.

SIM通常用于在GSM网络上运行和管理的智能手机中。 它是可移动的，用户可以在任何支持的智能手机上使用它。

SIM卡存储什么信息？ (What information does a SIM card store?)

The SIM card carries essential information back and forth to the user's network and it also carries some of his personal and private data.

SIM卡可将重要信息往返于用户的网络，也可以携带其一些个人和私人数据。

• Phone number

  电话号码

• Address book

  地址簿

• Network authorization data

  网络授权数据

• Text messages

  短信

• Personal security keys

  个人安全密钥

• Other data

  其他资料

A SIM also carries its,

SIM卡还带有

• Unique serial number (ICCID)

  唯一序列号(ICCID)

• International Mobile Subscriber Identity (IMSI)

  国际移动订户身份(IMSI)

• Security information

  安全资讯

• Ciphering information

  加密信息

• And, temporary information associated to the local network, etc.

  并且，与局域网相关的临时信息等。

SIM卡尺寸 (SIM Size)

The SIM size was nearly the size of a credit card when it was first developed. But the SIM quality size which discovered later carries a size of 15mm by 12mm. Now these days, micro and nano-SIM cards are used in some smartphones which are distinct in sizes.

SIM卡的大小几乎是刚开发时的信用卡大小。 但是后来发现的SIM质量尺寸为15mm x 12mm。 如今，微型和纳米SIM卡已在尺寸不同的某些智能手机中使用。

历史 (History)

In 1991, the first SIM card was developed by Munich smart-card maker Giesecke and Devrient. The SIM, in the beginning, was identified and stated by the European Telecommunication Standards Institute.

1991年，慕尼黑智能卡制造商Giesecke和Devrient开发了第一张SIM卡。 最初，SIM卡是由欧洲电信标准协会识别并声明的。

GSM与CDMA的区别 (Difference between GSM and CDMA)

GSM	CDMA
GSM is particularly for SIM.	CDMA is particularly for headset or phone.
GSM stands for Global System for Mobile communication.	CDMA stands for Code Division Multiple Access.
Technology supported FDMA and TDMA.	Technology supported CDMA.
The GSM is fundamentally based on wedge spectrum called a carrier.	The CDMA is fundamentally based on spread spectrum technology.
GSM has slow data rate in network.	CDMA has fast data rate in network.
Less security in GSM.	More security in CDMA.
GSM uses EDGE data transfer technology.	CDMA uses EVDO ready data transfer technology which has faster data transfer.
As the GSM signals are concentrated in the narrow bandwidth, signals can be detected easily.	The signals cannot be simply and easily detected in CDMA.
GSM is roaming over 80% of the world’s mobile network.	CDMA is roaming exclusively in the United States, Canada and Japan.
GSM phones continuously emit wave pulses. Consequently, there is a requirement to diminish exposure to electromagnetic fields.	CDMA phones do not have these wave pulses.

GSM	码分多址
GSM特别适用于SIM。	CDMA特别适用于耳机或电话。
GSM代表全球移动通信系统。	CDMA代表码分多址。
技术支持FDMA和TDMA。	技术支持CDMA。
GSM基本上基于称为载波的楔形频谱。	CDMA基本上基于扩频技术。
GSM网络中的数据速率较慢。	CDMA在网络中具有快速的数据速率。
GSM中的安全性较低。	CDMA中的更高安全性。
GSM使用EDGE数据传输技术。	CDMA使用了EVDO就绪的数据传输技术，该技术具有更快的数据传输速度。
由于GSM信号集中在窄带宽中，因此可以轻松检测到信号。	在CDMA中不能简单容易地检测到信号。
GSM正在漫游全球80％以上的移动网络。	CDMA仅在美国，加拿大和日本漫游。
GSM手机不断发出波脉冲。 因此，需要减少对电磁场的暴露。	CDMA手机没有这些波动脉冲。

翻译自: https://www.includehelp.com/dictionary/sim-full-form.aspx

sim800 模式切换