Ericsson RBS 2216 900 MHz base station teardown

The Ericsson RBS 2216 is a 900 MHz GSM base station that would have been installed at the base of a antenna somewhere out in the field of mobile telecommunication networks.

The enclosure contains one BFU-31 battery fuse and relay unit, three PSU-AC 27.2 VDC 1520 Watt power supplies, one DXU-31 central processing unit and 6 DRU9E-01 power amplifier and bandpass filters.

I will go through the different units starting with the battery fuse unit, then the CPU, then the power supply and at last, which also have a long teardown video, the power amplifier.

Battery fuse unit BFU-31

The battery fuse unit has two large connectors for the battery and some other external unit that I am not sure what is. The reason for knowing there is another external unit is that the connector marked “RBS” is in series with the “Batt” connector and the relays inside only handle one wire potential.

The long green connector has external alarm options from malfunction in the fuse unit. There is 8 pairs of NO/NC relays to be used. A small microcontroller on the board has feedback from various position switches on the large relays/fuses, voltage feedback and current feedback from a current transformer.

The unit contains a 80 VDC 270 A circuit breaker, a 260 A relay CZJ-260S/30.60A and 80 A relay CZJ-80S/30.60A. A Honeywell CSNS300M-001 current transformer that can measure up to 600 A DC or 825 A AC.

Central processing unit DXU-31

I think that the actual computer CPU is the PowerGarp RGP 101 1192/1 R3A since it has 512 MB SDRAM associated with it. I have not been able to find any further information on this IC.

Communication and network is handled by the Infineon QuadFALC PEF22554 HT IC.

I guess that the telecommunication protocol handler is the Ericsson VP22295-2 CPU which is connected to the Y-link ports and a 32 MB CF card.

The CF card contains 91 files and 2 sub folders with a total of 22.6 MB of data. All the files are without file extensions and on a FAT formatted file system. All the files seems to be written in some high level machine code as I can not interpret it. About half of the files does however also contain plain text which is mostly status and error messages. Following is the content of a file called “COLD_29K” which seems to be a cold start routine with error messages.

# – Coldstart
# – Processor revision < B4. Halting.
# – Restart counter limit exceeded.
# – Page mode not enabled.
# – Halting, no base appl found.
# – Starting DXU base appl.
# – Starting TRU base appl.
# – Starting ECU base appl.
# – Uncompress start.
# – PLS appl start.
# – Initiating all RAM.
# – Coldstart parity trap occured.
# – chc: 0x cha: 0xpc1: 0x cps: 0x# – Gr95 content: 0x

There are several other references in file names and within files to “29K” which seems to be the call name of their microcontroller.

Power supply unit PSU AC

There is not much to tell about the power supply unit. It is a solid piece of hardware that can deliver 1520 Watt power at 27.2 VDC. There is some trimpots in the middle of the PSU when you have the plate and heat sink removed, the one sitting closest to the middle of the group of three is able to adjust the output voltage, so it is possible to set it up to just about 28.2 VDC for use in HAM radio applications.

Power amplifier and band pass filter DRU9E-01

I made a video that describes the teardown of the amplifier and bandpass filter in much greater detail.

Different parts of the board shown in close up.

The Ericsson Tarac X CPU with the markings ROP 1011503/R1A F751500GPA 980 75P0P88 C has a total of 256 MB SDRAM.

The PowerGarp CPU with the markings RGP 101 1192/1 R3A has a total of 512 MB SDRAM

The couplers are Anaren Xinger II XC0900

The HDSL front end is a Analog devices AD7346A that converts the High-bit-rate digital subscriber line (HDSL)telecommunications protocol into a analog signal.

The transmiting transistors are 2x PTF080901E LDMOS RF Power Field Effect Transistor 90 W, 869–960 MHz.

The 20db attennuator is a RFP1398 rated for 100 Watt.

The receiving amplifiers have eight Analog devices AD7724 Dual CMOS Sigma-Delta modulators to convert the analog signal into a high speed 1-bit data stream.