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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.

DUG20_01_front_complete.jpg

Technical data

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

Flash

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 = Installatin DataBase).

DUG20_01_CF-slot_detail.jpg

Connections

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")

DUG20_01_ETB_ETA_detail.jpg

Pinout:

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

DUG20_01_ESB_detail.jpg

LMT B, LMT A, EC, GPS

DUG20_01_LMT_GPS_detail.jpg

LMT A

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

LMT B

Site-LAN and LMT B

FIXME

EC

"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.

GPS

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 https://www.te.com/usa-en/product-1982299-3.html with associated crimp contacts.

DUG20_01_DC_in_detail.jpg

Connector on the Back

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

DUG20_01_backplane_detail.jpg

LEDs

DUG20_01_LED_detail.jpg

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

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