Miscellaneous Projects » Ericsson RBS 6xxx

h1. 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.

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h2. Technical data

* 48V DC supply power

* 70W maximal power consumption

* Size: 8U x 31mm x 250mm

* Weight: < 2kg

h2. 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).

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h2. Connections

h3. Front Haul

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

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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).

h3. 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")

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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.

h3. ESB port

note that its a bit smaller than the sfp slots

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h3. LMT B, LMT A, EC, GPS

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h3. 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|

h3. LMT B

Site-LAN and LMT B

FIXME

h3. 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.

h3. 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

h3. 48V DC in

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

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h3. Connector on the Back

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

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h2. LEDs

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h2. Overview Pictures

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