Retronetworking » OCTOI - Osmocom Community TDM over IP

h1. OCTOI Event PBX

The OCTOI Event PBX are a couple of modified/enhannced 3U rackmount PBX systems which we can bring to retrocomputing / hacker events or museum exhibitions to provide a temporary point of connection to the OCTOI network.

They contain everything that's needed to connect to the network:

* An Auerswald COMmander 2 Basic PBX with

** one 8 port S0 line card (each S0 bus available on two RJ45 connectors)

** one 8 port analog line card (each analog port available on one RJ45 connector)

** one S2M (PRI) line card (connected to the icE1usb)

* the icE1usb device

* an embedded GNU/Linux computer (Beaglebone green) to run osmo-e1d and run the TDMoIP protocol endpoint

* an internal ethernet switch to allow access to the Auerswald

The idea is that you bring this unit to an event, connect it to power and ethernet (with internet access), connect some Phones/Modems/... and be ready to use the OCTOI network.

h2. Photos

h3. Front view with open lid

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h3. Internal view showing Ethernet switch, icE1usb and beaglebone green

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h2. Manufacturing

h3. Steps, rough outline

* drill mounting holes for combined 12V (switch) and 5V (beaglebone) PSU (Mean Well RD-35A) in the back plate

** do not mount the power supply yet, as  you won't be able to reach the terminal philips screws anymore

* configure GS305E ethernet switch (admin interface on 192.168.0.239 as described in manual)

* mount GS305E ethernet switch using mounting tape (make sure to clean surfaces first). It fits perfectly in the gap between Auerswald blue plastic carrier and the right side panel of the 3U 19" housing

* drill mounting holes for beaglebone into right side panel

* mount beaglebone using 5mm M3 hex spacers, M3 nuts and M3x6mm screws (nuts on beaglebone top PCB side, screws from outside of right side panel)

* use 2-wire USB-micro-B cable to connect 5V terminals of power supply to beaglebone

* use 2-wire 2.1mm/5mm barrel connector cable to connect 12V of power supply to Ethernet switch

* AC wiring

** remove PBX mainboard to  remove the L and N wires from its AC input (three PH1 screws)

** crimp and connect N (blue) and L (brown) wire (1.0/1.5mm2) with cable-end-sleeves and attach to PBX mainboard AC input

** re-mount the PBX mainboard (three PH1 screws)

** crimp and connect PE wire (1/1.5mm2) with cable-end-sleeve (power supply side) and ring terminal (attach to grounding bolt)

** crimp and connect N (blue) and L (brown) wire (1.0/1.5mm2) with cable-end-sleeves and attach to power supply

** Use one 3-way "Klapp-Wago" (Wago 222-413) clamps for L and N to connect power supply, PBX mainboard and AC input

* mount the power supply to the back panel using two M3x4 screws

* replace the existing fan with a low-noise fan (like Noctua NF-8A FLX). The PBX consumes very little power (20W idle, with switch/beaglebone/ice1usb maybe 30W) and even only the slightest airflow is sufficient.  No need for a noisy high-rpm fan.

* Ethernet wiring

** unplug the RJ45 pigtail from the PBX mainboard and plug it in switch port 2

** use a 50cm patch cable to connect the PBX mainboard with switch port 3

** use a 25cm patch cable to connect the beaglebone with switch port 5

* icE1usb

** use USB-C to USB-A cable to connect icE1usb to USB port of beaglebone

** crimp an E1 cross-over cable using two 8P8C RJ45 plugs and ~ 20cm of CAT5 cable; use it to connect PBX S2M card to line0 of icE1usb

** come up with some kind of panel-mount SMA pass-through for the GPS input signal. Example picture shows a [[osmo-lab-rack:Bgt-keystone6]], but you can also simply drill a 6mm hole into a blank face plate.

** use ~20cm SMA pigtail to connect SMA face plate pass-through to GPS input SMA jack of icE1usb

** mount icE1usb; an easy option is to remove the rubber gaskets from the icE1usb and use mounting tape to glue it to the top of the GS305E ethernet switch