Nokia EKSOS - use as ATA


I have my hands on a Nokia EKSOS rack with a POTS line card, and know nothing about that device.

My goal is to connect a larger number of analogue telephones to my Asterisk exchange, i.e. use it as an advanced Analog Telephone Adapter, supporting many lines, pulse dialing and 16 kHz metering tones. Is that generally a reasonable attempt?

Thanks a lot for documenting your findings on this site and wiki. Yet, I’m not sure I completely understand the overall architecture.

It seems to make it all work, what’s needed is some adapter that speaks ETSI/ITU V5 with the Nokia EKSOS on the one side, and on the other side, speaks something that an Asterisk channel driver supports, like SIP/RTP or some of the others ones.

Now I am not sure whether retronetworking/osmo-v5: An open source implementation of the LE (Local Exchange) side of the ETSI/ITU V5 interface, in order to talk to Access Multiplexers (AN), such as Nokia EKSOS, DeTeWe ALIAN, etc. - osmo-v5 - Osmocom gitea is such a thing or not. I haven’t been able to make much sense of the documentation regarding how it is being run and used.

Thanks a lot!

Indeed, it is.
You can use a DAHDI-compatible E1 interface (something like the icE1usb or a Digium card) to expose the V5 side to your EKSOS (osmo-v5 uses libosmo-abis internally) and the other side will be osmo-cc.

The project was used successfully at Chaos Communication Camp last year, but there’s pretty much no documentation and you’ll pretty much need to be able to read the source code to get it configured/setup/debugged.

Not sure about support for the metering impulses at the moment, either, but I guess it could be implemented.

I recall that there was a RetroNetCall / OsmoDevCall related to this topic, where osmo-v5 was presented in detail, but I’m not sure if that was recorded / at least I couldn’t find the recording right away. Maybe someone else has a link for you.

Not sure about support for the metering impulses at the moment, either, but I guess it could be implemented.

It’s implemented with the current versions of osmo-cc-pstn-endpoint, osmo-cc-misdn-endpoint and osmo-cc-router. Supported methods:

  • 16 kHz metering pulses
  • Line reversal metering pulses (“Schwellimpulszählung”)
  • Line reversal on connect
  • AOC-D, AOC-E
  • AOC-S (especially for Bluephones)

You need to enable the metering method within the PSTN/mISDN endpoint (metering/lr-metering/aocd/aocs) and select a metering rate within a osmo-cc-router call processing script (e.g. metering connect_units=1 period=30.3)

Thanks a lot for those clarifications.

icE1usb sounds really a great fit (and kudos for making it open source hardware), because USB works better for the energy saving mini-computer form factor I’m using, rather then requiring Digium PCI cards. On the other hand, I’m hesitating to order it for ~285 Euro while the remaining steps of what I need, for example to get osmo-v5 running, seem to be not comprehensively documented. My C isn’t that great to reverse engineer, for example I see there’s a config file being read with undocumented format, being parsed by a call to vty_read_config_file but that implementation is not anywhere in the osmo-v5 repository… Well I’ll look a bit more in dept in the coming days.

Take a look into my osmo-v5-tools repository. I’ve uploaded some example configuration files to eksos-example-config.

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A bit more information about the physical setup regarding power supply etc.

I’m using a Meanwell GSM90B48-P1M (90W 48V), which should be sufficient for up to 6 line interface cards. It has no ground connection on the primary side, which is important since grounded power supplies have the negative polarity grounded, but the EKSOS has positive polarity grounded and you’ll get short circuits if connecting those together. Ungrounded power supplies have two pins for the 230V connection (C7 connector), instead of three.

Normally, you have to connect all three power connectors, but you can reduce that to one input and one bridge cable.

If you remove the line cards, you can get access to a screwed plate in the backplane. Remove it, and you have four jumpers there. Connect J1 and J3 to the right to bridge the power rails, which is sufficient for the 90W power supply.

My setup:

Thanks for sharing experiences here. I think something important reference information like the jumper / power supply information would best be added to the wiki to make it easy for people to find at a later point, without reading through lots of forum posts.


laforge has promised me one EKSOS and one ALIAN. Before I get them, I was wondering what I should already buy as equipment to power them up. I know that I need a ~90W -48V Power supply. That won’t be an issue. Further, do I need any fancy stuff like 10base2 ethernet? Would anybody know where to source the connectors for the lines from? Is there anything I am forgetting? As a matter of course, I need E1s, but that is not a problem.



do I need any fancy stuff like 10base2 ethernet?

Not for the EKSOS.

Would anybody know where to source the connectors for the lines from?

I’ve got them from A*express. If you accept the pain ordering things there, search for these things:

  • Line connector: “5 Pcs DIN 41612 Connector 3 Rows 96 Pin Plug Receptacle Female Sockets Right Angle Vertical Through Hole PCB Solder Pitch 2.54MM”, type “Straight female”
  • E1 connector: “5PCS DIN 41612 Connector 3 Rows 48 Positions Din Female Sockets Receptacle Vertical Through Hole PCB 3x16 4Pitch 2.54MM” and either remove the coding frame inside the EKSOS plug, or file matching gaps into the female connector.
  • Power connector: Look for “3 pin elevator connector”, type male.
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Thank you! I ordered everything off Digikey. Probably more expensive but I am sure I’ll get it.