DTE/DCE and CSU/DSU

DTE/DCE and CSU/dsu dte: data terminal device. Such as a computer. DCE: a data communication device, such as a modem. CSU: Channel service unit. DSU: Data Service Unit. CSU (Channel service unit): A digital interface device that connects an end user to a local digital phone loop. Generally, it and DSU are collectively referred to as CSU/DSU. DSU (data business unit): Refers to a device used in digital transmission. It can adapt the physical layer interfaces of DTE devices to communication facilities such as T1 and E1. The data Business Unit is also responsible for signal timing and other functions. It is usually mentioned with CSU (Channel business unit), called CSU/DSU. DCE (data communication device or data circuit terminal device): the connection between the device and its communication network forms the user network interface of the network terminal. It provides a physical connection to the network and forwards traffic, and provides a clock signal for synchronizing data transmitted between the DCE device and the DTE device. Both the modem and interface card are examples of DCE devices. DTE (data terminal device): Refers to a device located on the user's network interface client. It can act as a source, sink, or both. A data terminal device connects to a data network through a data communication device (such as a modem), and usually uses the clock signal generated by the data communication device. The distinction between DTE and DCE of data terminal devices, such as computers, protocol translators, and multi-channel reducers, is only for serial ports. Routers usually connect to wide-area networks through serial ports. Serial Port V.24 (25-pin) usually requires that the DTE consists of 2nd pins as TXD (send data line), 3rd pins as RXD (receive data line), and (other pins: 7 is the signal ground, 4 is DTS, 5 is RTS, 6 is DTR, 8 is the DCD, and includes the sending clock, receiving clock, and so on, there are specified specific pins ), serial V.35 (34-pin) is the standard of communication interface used by routers, but V.35 uses differential signals for transmission. The transmission and acceptance are undertaken by two signal lines respectively. The DCE device is usually connected to the router, so the distribution of the pins is opposite, that is, 2 is the receive (but also known as TXD), and 3 is the send. Therefore, the router is usually a DTE device, and the modem, GV converter, and other transmission devices are usually specified as DCE. In fact, for standard serial ports, it is usually determined from the appearance whether it is DTE or DCE, DTE is a needle (also known as the public head), DCE is a hole header (also known as the mother head ), these two interfaces can be connected together. It is generally used to differentiate interfaces. For example, a vro is on the edge of the network. It has an S0 port and needs to learn some parameters from another vro, we don't need to configure the "clock rate" in this S0 port, it learns from the other side. In this case, it is DTE, and the other party is DCE. DTE stands for Data Terminal Equipment, a digital Terminal device. It refers to a general Terminal or computer. It may be a large, medium, or small computer, or a printer that only receives data. DCE stands for Data Circuit-terminating Equipment, a digital communication device, usually a modem, multiplexing, or digital device. DTE, DCE difference DCE side provides the clock, DTE does not provide the clock, but it relies on the clock provided by DCE to work. For example, the connection between a PC and a MODEM. A pc is a DTE, and a MODEM is a DCE. DTE can distinguish its interface from a dot matrix on the hardware, and the interface of DCE is a hole. CSU/DSU: Channel Service Unit/Data Service Unit 1. CSU (Channel service unit): A digital interface device that connects an end user to a local digital telephone loop. Generally, it and DSU are collectively referred to as CSU/DSU. DSU (data business unit): Refers to a device used in digital transmission. It can adapt the physical layer interfaces of DTE devices to communication facilities such as T1 and E1. The data Business Unit is also responsible for signal timing and other functions. It is usually mentioned with CSU (Channel business unit), called CSU/DSU. 2. CSU/DSU functions CSU to receive and transmit signals from and to the WAN Line, and to provide shielding for interference between the two sides of the line. CSU can also respond to the echo signals sent by telephone companies for the purpose of Detection. DSU performs line control, converting between input and output frames in the following forms: RS-232C, RS-449 or V.35 frame of LAN and tdm dsx frame on T-1 line. DSU management time-sharing error and signal regeneration. DSU provides interfaces similar to modem and computer functions like data terminal devices and CSU. CSU and DSU are sometimes used as independent products and are sometimes integrated with routers. CSU/DSU data terminal device interfaces are generally compatible with V.35 and RS232C or other same serial interfaces. q: CSU/DSU: Channel service unit/Data Service Unit A: Channel Service Unit (CSU) is A device that can set LAN) the data frame of the communication system is converted into a data frame suitable for the wide area network, or reverse conversion. A Data Service Unit is also a device that can protect and diagnose Telecom lines. A typical application of these two devices is to combine them into an independent unit, which is actually to combine them into a complicated and expensive modem. Taking the use of the channel service unit (CSU)/Data Service Unit (DSU) as an example, first, lease a data cable from the telephone company or ISP for the enterprise (may be T1, T3 or some T1/T3 lines), and then install CSU/DSU on the user terminal, CSU/DSU must also be installed on the telephone company or ISP terminal. The channel Service Unit (CSU) sends or receives signals from the Wan line, and provides an electrical interference shielding from both sides of the unit. CSU can also return the return signal used by the telephone company for detection. DSU manages Line Control and time division multiplexing (TDM) between RS-232C, RS-449 or V.35 data frames on LAN and T-1 lines) converts the input and output between data frames in DSX. DSU controls the timing error and signal refreshing. DSU provides a modem-like connection between a computer that acts as a data terminal device (DTE) and a CSU. CSU/DSU is produced as a separate product, but is sometimes used as a part of a T-1WAN Nic. CSU/DSU data terminal device interfaces are generally compatible with V. xx and RS-232C or similar serial interfaces.