DUS 31 » History » Version 3
laforge, 11/03/2020 03:31 PM
1 | 1 | laforge | h1. DUS 31 |
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3 | 3 | laforge | {{>doc}} |
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5 | 2 | laforge | The DUS 31 is the first digital unit (we know) which supported multi-standard on the same DU. As you can run both LTE and GSM on the same unit, it basically combines a DUL and a DUG. |
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7 | The GSM back-haul is no longer exposed via E1/T1 TDM lines, but uses _Ericsson PacketAbis over IP_, which is basically the L2TP/HDLC based protocol stacking that the [[SIU 02]] or the [[TCU]] would have traditionally generated. |
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9 | 1 | laforge | h2. Mass Storage |
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11 | The unit has an internal 8GB USB Mass Storage device, as a _Micron Embedded USB Mass Storage Drive (e230)_. You can think of it as a USB thumbdrive, but not with an exterenal USB A plug, but with a 9-pin 2-row 2.54mm pitch receptacle, which can be plugged directly onto USB 2.0 headers on mainboards. |
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13 | The partition table looks as follows: |
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14 | <pre> |
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15 | Disk ./dus31.dd: 7.56 GiB, 8120172544 bytes, 15859712 sectors |
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16 | Units: sectors of 1 * 512 = 512 bytes |
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17 | Sector size (logical/physical): 512 bytes / 512 bytes |
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18 | I/O size (minimum/optimal): 512 bytes / 512 bytes |
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19 | Disklabel type: dos |
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20 | Disk identifier: 0x00000000 |
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22 | Device Boot Start End Sectors Size Id Type |
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23 | ./dus31.dd1 4 1999999 1999996 976.6M 21 unknown |
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24 | ./dus31.dd2 2000000 13999999 12000000 5.7G 21 unknown |
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25 | </pre> |
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26 | 3 | laforge | |
27 | h2. LMT cable |
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29 | The DUS31 combines the serial UART (traditionally "LMT A") and the management ethernet port (traditionally "LMT "B) in a single RJ45 connector. You need a special breakout cable to split those two signals. As it is a purely mechanical/electrical adapter without any active parts, it's relatively easy to build one DIY. |
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31 | TODO: connector layout |
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33 | We have created a small OSHW circuit board design of a break-out board, its design files can be found at https://git.osmocom.org/osmo-small-hardware/tree/dus-lmt-breakout |