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APC Master Switch Serial Cable

September 1, 2025September 1, 2025 G1FEF Hardware

The APC Master Switch series PDUs have an RJ11 socket for the serial port, if you have a spare Cisco serial cable lying about here is a quick trick to make up a 9 pin D-Type socket to RJ11 plug cable: Cisco Pin Colour RJ11 Pin Description 1 Grey CTS 2 Blue DSR 3 Green […]

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Cisco SPA504G VoIP phones

January 1, 2025May 27, 2025 G1FEF Uncategorized

These phones are available at very low cost, e.g. on eBay and work great as a VoIP phone. They support up to 4 “lines” or SIP accounts and are very easy to program. For anyone interested in hacking the onboard CPU there is a serial interface available on the PCB – Look for “J3” which […]

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M590E hardware mods

November 21, 2018January 6, 2025 G1FEF Hardware

The M590E is a 2G GSM module that, at the time of writing, can be bought as a kit on eBay for around £1 complete with PCB and components.

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Turning POE on and off on the Cisco 3750 via SNMP

September 8, 2018September 8, 2018 G1FEF Programming

I recently had a requirement to be able to turn the POE power off / on on specific ports on a remote c3750 POE switch in order to reboot devices that kept crashing.

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Asterisk systemd startup script

September 8, 2018September 8, 2018 G1FEF System admin

The systemd startup script “out of the box” (at least up to version 15.5) for Asterisk does not work properly: on rebooting the server the ownership of /run/asterisk (symlink /var/run/asterisk) reverts to root.root instead of asterisk.asterisk The reason for this is that the o/s removes and re-creates the /run/asterisk directory on reboot. The solution is […]

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Setup MySQL / MariaDB master slave replication

July 2, 2017August 13, 2019 G1FEF Database, System admin

mysql -u root -p < dump.sql How to setup a single master with one or more readonly slaves

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Setting up and using your own SSL CA

May 31, 2017July 2, 2017 G1FEF System admin

This guide shows how to setup a Certificate Authority on Centos 7

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Centos 7 + Postfix + Amavisd-new + Clamav + OpenDKIM + OpenDMARC

May 28, 2017July 2, 2017 G1FEF System admin

How to setup Postfix, Amavisd-new, Clamav, OpenDKIM & OpenDMARC on Centos 7

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Setting up a Galera MariaDB Cluster

May 27, 2017July 2, 2017 G1FEF Database, System admin

How to setup a Galera MariaDB Cluster

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Update MediWiki

May 11, 2017July 2, 2017 G1FEF System admin

How to update MediaWiki

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  • APC Master Switch Serial Cable
  • Cisco SPA504G VoIP phones
  • M590E hardware mods
  • Turning POE on and off on the Cisco 3750 via SNMP
  • Asterisk systemd startup script

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