Nokia EKSOS N20 DIY carrying case » History » Version 4
laforge, 08/27/2023 11:45 AM
| 1 | 1 | laforge | h1. Nokia EKSOS N20 DIY carrying case |
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| 3 | In preparation of the first hacker event where we wanted to offer ISDN Uk0 service (see [[ISDN_at_CCC_Camp_2023]]) we wanted to build portable, self-contained and ruggedized systems from the Nokia EKSOS. |
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| 4 | |||
| 5 | The systems should contain |
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| 6 | * EKSOS N20 shelf with mandatory NCU and some subscriber line cards |
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| 7 | * a number of subscriber ports broken out to RJ45 connectors |
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| 8 | * a 48V power supply |
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| 9 | * an [[Osmocom_icE1usb]] plus an embedded Linux board to run TDMoIP for the V5 back-haul |
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| 10 | ** should have at least two Ethernet ports so we can also back-haul the Q3 management interface to a remote location |
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| 11 | * some fans for active cooling as it is getting rather hot in the sun outdoor on a camp |
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| 12 | * ruggedized enclosure to make sure the equipment survives transportation unharmed |
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| 13 | |||
| 14 | h2. Enclosure |
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| 16 | 3 | laforge | The enclosure is made of wooden panels. |
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| 18 | h3. wood corpus |
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| 20 | h4. Assembled enclousre body |
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| 22 | !20230801_203832.jpg! |
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| 24 | h4. Milling left and right sides to accomodate screw heads |
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| 26 | Unfortunately the EKSOS shelf mounting flanges contains a number of screw heads and other protrusions, which require the side panels to be milled |
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| 27 | |||
| 28 | !20230801_203546.jpg! |
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| 30 | h4. Bottom side / gliders |
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| 31 | |||
| 32 | !20230801_203821.jpg! |
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| 34 | 1 | laforge | h3. Fans / Cooling |
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| 36 | h2. Power Supplies |
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| 38 | 4 | laforge | The power supplies are mounted in the rear part of the bottom panel |
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| 40 | !20230804_192817.jpg! |
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| 42 | h3. 48V: MeanWell RSP-150-48 |
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| 43 | |||
| 44 | This supply is used for powering all 3 rails of the EKSOS shelf: |
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| 45 | * odd numbered line cards |
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| 46 | * even numbered line cards |
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| 47 | * signaling voltage |
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| 48 | |||
| 49 | I've used the trimmer potentiometer to trim the output voltage to the maximum (+5%). |
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| 51 | h3. 12V: MeanWell RSP-12-35 |
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| 53 | This 12V supply is used to power the nanoPi R5S as well as the fans. |
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| 57 | 1 | laforge | h2. Subscriber port break-out |
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| 59 | h2. icE1usb + Linux SBC |
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| 60 | |||
| 61 | Given that we needed multiple Ethernet ports in a Linux SBC with passive cooling, there weren't really all that many options on the market. I went for a *nanopi R5S*, which has 3 ethernet ports. |
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| 62 | |||
| 63 | h3. nanoPI R5S 12V DC re-work |
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| 64 | |||
| 65 | For some weird reason, the nanoPi R5S *only* supports USB-PD. There is no straight DC supply connector for feeding e.g. 12V to it. Not even an unpopulated header on the circuit board. |
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| 66 | |||
| 67 | This meant that it simply wouldn't power up at all if 12V were applied from the 12V mean-well power supply in the unit. Luckily, @tnt and I came up with some hardware re-work to modify the R5S to accept a 12V DC input without any USB-PD signaling: |
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| 68 | |||
| 69 | FIXME: Describe the rework |
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| 70 | |||
| 71 | h4. Unmodified R5S |
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| 72 | 2 | laforge | |
| 73 | !20230809_233333.jpg! |
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| 74 | |||
| 75 | h4. R5S with removed resistor |
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| 76 | |||
| 77 | !20230809_233308.jpg! |
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| 78 | |||
| 79 | h4. R5S with additional pull-up resistor |
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| 80 | |||
| 81 | !20230809_233231.jpg! |
