DUL 20¶

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

• Table of contents
• DUL 20
  • Further Reading
  • Connectors
    • PWR
    • GPS (RJ45)
    • EC (RJ45)
    • AUX (RJ45)
    • LMT A (RJ45)
    • LMT B (RJ45)
    • TN A (RJ45)
    • TN B (SFP)
    • IDL (HSIO)
    • RI A..F (SFP)
  • Overview Pictures
  • Accessing it
    • SSH via LMT-B
  • Mass Storage

Further Reading¶

• DUL 20 Configuration
  • DUL open5gs configuration
  • Moshell
• DUL Shell Commands

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.

GPS (RJ45)¶

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

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.

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.

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.

Overview Pictures¶

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.