The earliest method of delivering telecommunications is the ( ).

[单选题]The earliest method of delivering telecommunications is the ______．A．telegraphB．telephoneC．e-mailD．letter

[单选题]Wireless telecommunications networks are generally implemented and administered using（）communication.This implementation takes place at the （）level of OSI model network structure.A．microwave B．radio C．FM D．AMA．physical B．link C．network D．transport

[单选题]Telecommunications stand for devices and systems that transmit electronic or optical signals across long distances. Telecommunications enables people around the world to contact one another, to access information instantly, and to communicate from re

[单选题]The earliest invasion of England is that by( )A.the IberianB.the DanesC.the

[单选题]The earliest invasion of England is that by( )A.the IberianB.the DanesC.the

[单选题](With the 4G telecommunications systems now starting to be deployed,people are looking towards the development of 5th generation or 5G technology services.Although the deployment of any wireless or cellular system take years,development of the 5G tec

[单选题]Passage TwoThe earliest immigrants to North America found Indians already living there. The Indians numbered about 500,000 at that time. Their society was a primitive society, but they lived peacefully and welcomed the white strangers to the land. Ho

[单选题]is a method used in Critical Path Methodology for constructing a project schedule network diagram that uses boxes or rectangles，referred to as nodes，to represent activities and connects them with arrows that show the logical relationships that exist

[单选题]is a method used in Critical Path Methodology for constructing a project schedule network diagram that uses boxes or rectangles, referred to as nodes, to represent activities and connects them with arrows that show the logical relationships that exis

[单选题]数字证书在International Telecommunications Union（ITU）的哪个标准中定义的？（）A . X.400B . X.25C . X.12D . X.509