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DUL 20

DUL is a Digital Unit for LTE. It contains the eNodeB function down to the baseband processing.

DUL20_01_front_complete.jpg

Further Reading

Connectors

PWR

48V DC connector. The negative rail is towards the edge of the unit. Also seems to power up fine at 36V

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

DUL20_01_DC_in_detail.jpg

GPS (RJ45)

Connection for an Ericsson GPS module, contains 1PPS and UART signals

DUL20_01_LMTA_GPS_detail.jpg

EC (RJ45)

Environment Control? Probably some RS-485 to control fans, power management, UPS, ...

AUX (RJ45)

?

LMT A (RJ45)

A RS-232 on RJ45 for Local Maintenane use. IT provides access to COLI (COmmand LIne).

The pinout is shown below. Please note it is different from RBS3000!, but identical to that of the DUG 20

RJ45 DB9 Name
1 5 GND
2 3 TXD (of PC)
3 2 RXD (of PC)

The [default?] baud rate settings are 9600 8N1.

This port provides RS-232 access to the OSE shell

LMT B (RJ45)

Site LAN Ethernet, for adminstrative purpose

This is the interface used for configuration of the DUL during installation.

DUL20_01_LED_TNA_LMTB_detail.jpg

TN A (RJ45)

Transmission Ethernet, i.e. the back-haul interface for S1. RJ-45

TN B (SFP)

Transmission Ethernet for optical back-haul. Can use normal SFP modules.

DUL20_01_TNB_IDL_detail.jpg

IDL (HSIO)

Inter-DU-Link for cross-connecting multiple DU.

RI A..F (SFP)

Radio Interface (CPRI) using either SFP transceivers for RRU connection or copper interconnect cables for RU.

DUL20_01_SFP_detail.jpg

Overview Pictures

DUL20_01_front_perspective.jpg DUL20_01_left_perspective.jpg DUL20_01_right_perspective.jpg DUL20_01_back_perspective.jpg DUL20_01_bottom_complete.jpg

Accessing it

SSH via LMT-B

It appears the DUL will always respond to 169.254.1.10/16, no matter what kind of real/other IP address has been set.

You have to use the following SSH config to speak the ancient cipher/key-exchange:

Host dul
        HostName 169.254.1.10
        KexAlgorithms diffie-hellman-group1-sha1
        Ciphers 3des-cbc

and then log in as the 'rbs' user with 'rbs' password.

Mass Storage

The DUL20 has an internal CompactFlash slot. The slot is only accessible when disassembling the unit, removing the circuit board from the enclosure.

It uses 2GB CFlash cards with no known partition table / format.

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