DUG 20

This is the second-generation GSM Digital Unit for RBS 6xxx. It combines the baseband processing and back-haul interface of up to 12 TRX, in 1..6 logical BTSs.

The DUG 20 is only compatible with the RUS and RRUS radio units, not with the older RUG units.


Technical data

  • -48V DC supply power
  • 70W maximal power consumption
  • Size: 8U x 31mm x 250mm
  • Weight: < 2kg


There is a CF slot on the left this device and it holds a 256mbyte CF card. The card contains a FAT filesystem with both the software as well as the configuration (IDB = Installation DataBase).



Front Haul

The DUG 20 has 6 SFP slots for the interface towards the radio units, labelled RI A..F

DUG20_01_SFP_1_detail.jpg DUG20_01_SFP_2_detail.jpg

This is where you connect your RUS or RRUS, either via direct-attach cables (usual for RUS), or via SFP transceivers and optical fiber (usual for RRUS).

Back-Haul interface

The back-haul interface is Classic T1/E1/J1 (ISDN) based. The DUG has four T1/E1/J1 lines exposed as two RJ45 connectors ("ET A" and "ET B")



RJ45 Line Signal
1 A RX tip (+)
2 A RX ring (-)
3 B TX tip (+)
4 A TX tip (+)
5 A TX ring (-)
6 B TX ring (-)
7 B RX tip (+)
8 B RX ring (-)

Same pinout as a Digium card with 2 lines per port.
So a cross-over cable is needed to connect to it.

ESB port

note that its a bit smaller than the sfp slots





LMT (Local Maintenance Terminal) A hosts a RS-232 port used for connecting to the DUG 20 from a PC running the OMT software.

RJ45 DB-9 (female) Signal
1 5 GND
2 3 TxD
3 2 RxD


Site-LAN and LMT B



"Enclosure Control". A (likely) RS-485 based site-local bus between different parts, particularly any power supply / climate systems and the digital unit. Used for monitoring/alamrs in case of environmental failure.


This port is meant for attaching an external GPS receiver. The connector includes
  • RS485/422 receiver for NMEA from the GPS
  • RS485/422 transmitter for command to the GPS
  • RS485/422 receiver for 1PPS signal from the GPS
  • 12V power supply for the GPS

-48V DC in

Connectory type is a with associated crimp contacts.


Telecom equipment such as the DUG 20 typically has a positive ground system also known as "negative" 48 Volt1.

Be aware (beware!) of short circuits. The chassis of the DUG and any other ground terminal on any port is connected to the +48v terminal, If any other equipment with a (typical) negative ground system is connected to the same DC supply as the DUG, there will be voltage difference between the ground terminals (and chassis) of this equipment and the DUG.

Connector on the Back

This connector is not used during normal operation. We assume it is for factory / service use only.




Overview Pictures

DUG20_01_front_perspective.jpg DUG20_01_left_perspective.jpg DUG20_01_right_perspective.jpg DUG20_01_back_perspective.jpg DUG20_01_bottom_complete.jpg

Internal pictures

dug20_pcba_top.jpg dug20_pcba_bot.jpg dug20_pcba_rj45.jpg dug20_pcba_rs232.jpg

Spare Parts

  • 4-port RJ45 assenmbly including LMT ports: Amphenol RJHSE538004
  • RS232 transceiver of LMT A port: ST3232ECTR


Files (19)
DUG20_01_bottom_complete.jpg View DUG20_01_bottom_complete.jpg 177 KB roh, 05/07/2020 10:06 PM
DUG20_01_back_perspective.jpg View DUG20_01_back_perspective.jpg 436 KB roh, 05/07/2020 10:06 PM
DUG20_01_front_perspective.jpg View DUG20_01_front_perspective.jpg 105 KB roh, 05/07/2020 10:06 PM
DUG20_01_front_complete.jpg View DUG20_01_front_complete.jpg 239 KB roh, 05/07/2020 10:06 PM
DUG20_01_left_perspective.jpg View DUG20_01_left_perspective.jpg 387 KB roh, 05/07/2020 10:06 PM
DUG20_01_right_perspective.jpg View DUG20_01_right_perspective.jpg 358 KB roh, 05/07/2020 10:06 PM
DUG20_01_backplane_detail.jpg View DUG20_01_backplane_detail.jpg 312 KB roh, 05/07/2020 10:06 PM
DUG20_01_CF-slot_detail.jpg View DUG20_01_CF-slot_detail.jpg 347 KB roh, 05/07/2020 10:06 PM
DUG20_01_LED_detail.jpg View DUG20_01_LED_detail.jpg 336 KB roh, 05/07/2020 10:06 PM
DUG20_01_ESB_detail.jpg View DUG20_01_ESB_detail.jpg 334 KB roh, 05/07/2020 10:06 PM
DUG20_01_SFP_2_detail.jpg View DUG20_01_SFP_2_detail.jpg 335 KB roh, 05/07/2020 10:06 PM
DUG20_01_SFP_1_detail.jpg View DUG20_01_SFP_1_detail.jpg 353 KB roh, 05/07/2020 10:06 PM
DUG20_01_DC_in_detail.jpg View DUG20_01_DC_in_detail.jpg 324 KB roh, 05/07/2020 10:17 PM
DUG20_01_ETB_ETA_detail.jpg View DUG20_01_ETB_ETA_detail.jpg 357 KB roh, 05/07/2020 10:17 PM
DUG20_01_LMT_GPS_detail.jpg View DUG20_01_LMT_GPS_detail.jpg 357 KB roh, 05/07/2020 10:17 PM
dug20_pcba_top.jpg View dug20_pcba_top.jpg 2.98 MB laforge, 03/26/2021 09:45 AM
dug20_pcba_bot.jpg View dug20_pcba_bot.jpg 1.83 MB laforge, 03/26/2021 09:45 AM
dug20_pcba_rj45.jpg View dug20_pcba_rj45.jpg 3.06 MB laforge, 03/26/2021 09:45 AM
dug20_pcba_rs232.jpg View dug20_pcba_rs232.jpg 2.18 MB laforge, 03/26/2021 09:45 AM

Updated by dexter over 1 year ago · 16 revisions

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