Retronetworking

h1. Nokia EKSOS N20 DIY carrying case

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.

The systems should contain

* EKSOS N20 shelf with mandatory NCU and some subscriber line cards

* a number of  subscriber ports broken out to RJ45 connectors

* a 48V power supply

* an [[Osmocom_icE1usb]] plus an embedded Linux board to run TDMoIP for the V5 back-haul

** should have at least two Ethernet ports so we can also back-haul the Q3 management interface to a remote location

* some fans for active cooling as it is getting rather hot in the sun outdoor on a camp

* ruggedized enclosure to make sure the equipment survives transportation unharmed

h2. Enclosure

h3. Fans / Cooling

h2. Power Supplies

h2. Subscriber port break-out

h2. icE1usb + Linux SBC

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.

h3. nanoPI R5S 12V DC re-work

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.

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:

FIXME: Describe the rework

h4. Unmodified R5S