3.  Like a server cabinet  The BTS3012 cabinet is purple gray in color and vertical in appearance

4.  The components are 1. Transmission subrack 2. Common subrack 3. DTRU subrack -0 4. Fan subrack 5. DTRU subrack-1 6. DAFU subrack 7. Power distribution unit 8. Signal lightning protection subrack

5.  located below the common sub-rack.  Reserves space for the baseband unit (BBU). › Such as SDH, › microwave transmission equipment

6.  Common subrack  The common subrack is installed below the fan subrack. It holds the following parts: › DTMU › DEMU › DATU › DCSU › DCCU › DABB › DPTU

7.  Dual Transmission or Timing Management Unit  an entity for basic transmission and control in the BTS3012.  It works as a main controller.  The DTMU is a mandatory module inserted in slots 0 and 1 (from left to right)

9.  Dual Environment Monitoring Unit  The DEMU performs the following functions: › Monitors the environment information sent from the smoke sensor, water sensor, temperature and humidity sensor, infrared sensor, and door control sensor › Collects alarm information and reports it to the DTMU

10.  Dual Antenna and TMA Control Unit  Controls the RET antenna  Feeds power to the TMA

11.  Combined cabinet Signal connection Unit is placed in slot 5 of the common sub-rack  The DCSU is a mandatory board  The DCSU performs the following functions: › Transmits clock signals, data signals, and control signals between the main cabinet and the extension cabinet › Transmits the clock signals, data signals, and control signals from the DTMU to the DTRU

12.  Cable Connection Unit is placed in slot 6.  The DCCU is a mandatory board.  The DCCU performs the following functions: › Transfers E1 signals › Transfers the control signals for the fans › Transfers the clock signals from the DAFU subrack

13.  Packet transmission unit can be installed in slot 3 or 4  The DPTU is mandatory  The DPTU performs the following functions: › Provides the interface for Abis over IP › Provides the BTS with the convergence function of a Hub › Provides the functionality of Clock Over IP

14.  The DTRU subracks can hold up to nine DTRUs

15.  Double-Transceiver Unit (DTRU) is placed in the double-transceiver subsystem of the BTS.  One DTRU consists of two TRXs  Baseband Processing Part › The baseband processing part performs the following functions: › Processing signaling, coding and decoding, interleaving and de-interleaving, modulation and demodulation › Supports RF loop test and switchover of the faulty phase-locked loop › Amplifying output power

16.  RF Transmitting Part › The transmitting part of the RF signals performs the following functions: › Modulates the baseband signals into RF signals and performs up-conversion, filtering, and RF hopping › Amplifies and outputs the RF signals  RF Receiving Part › The receiving part of the RF signals performs the following functions: › Demodulates the RF signals into baseband signals and performs RF hopping › Divides the received RF signals and performs receive diversity

17.  The fan subrack holds one fan box  a fan monitoring board consists of four fans.  The fan monitoring board detects the temperature at air inlets at bottom of the cabinet and automatically adjusts the fan speed

18.  Antenna Front-end Unit  The DAFU subrack can be configured with › DDPU › DCOM › DFCU or DFCB.

19.  Dual-Duplexer Unit  The DDPU performs the following functions: › Provides lightning protection through the ANT port › Detect VSWR alarms in the antenna system › Control the gains for the receive low noise amplifier › Transmits multiple routes of RF signals from the transmitter to the antenna

20.  Combining Unit  The DCOM combines two routes of TX signals from the DTRU, and then sends them to the DDPU

21.  The power distribution unit consists of the › DC lightning arrester, › EMI filter, › PGND bar, › Busbar terminal socket (top) › Busbar (right)

22.  The signal lightning protection subrack is installed on top of the cabinet. It is configured with the following boards: › DMLC › DELC › DSAC

23.  Monitor Signal Lightning-Protection Card  The DMLC performs the following functions: › Provides lightning protection for Boolean input and output signals › Provides lightning protection for analog signals that are transmitted from the smoke sensor, water sensor, door control sensor, infrared sensor, humidity and temperature sensor

24.  E1 Signal Lightning-Protection Card  The DELC performs the following functions: › Provides lighting protection for E1 signals

25.  Signal Access Card  The DSAC performs the following functions: › Provides six Boolean alarm inputs › Provides lightning protection for BITS clock signals