my friend has asked me to come and install a new switch he bought.

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The top two panels are just the panels that connect to the cabling throughout the floor. The third panel is the switch which I'm about to replace.

My question is, what is the box underneath it? Is has a networked hdd and a wireless phone thing standing on it. Close up:

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I would really like to know what it is and what it does before I start changing things. There is no existing network documentation. I'm guessing it might do something with the telephone lines as they are about 10 numbers on the premises.

Very grateful,



Well that looks like a PBX for a phone system to me. Above it to the right is a punch down block where, presumably, they have POTS lines coming in to "feed" the PBX.

  • Absolultally, that's 100% a PBX. You can even see its backup batteries tucked in the left-hand bottom side. There's also a WD MyBook and WiFi access point for those playing at home. – Mark Henderson Aug 31 '10 at 0:12
  • HaHa. I thought that was a WD! Either that or some crazy new Xbox. ;) – joeqwerty Aug 31 '10 at 0:22
  • 1
    Probably a KSU rather than a PBX. – Paused until further notice. Aug 31 '10 at 1:54

That looks like a PBX/voicemail server. The harddisk often holds the voicemails for the office.

There is often a VGA port for a monitor, so you could try and plug one in. That might give you the vendor name, version, etc.

  • 2
    There's a serial port on the edge of the third card from the right. I'd bet that access is via serial interface or Ethernet rather than VGA. The D-sub connectors on the right side may also be serial ports, but they aren't visible clearly enough to make out. It looks like there are two RCA jacks probably for an external on-hold music source. It's too bad there's no logo/name visible. I don't think the external WD is for the KSU. It seems to have its own HD or Compact Flash on the card with the yellow warning label. – Paused until further notice. Aug 31 '10 at 1:59

Looks like a PBX to me.


It certainly is a PBX. The outgoing cables terminating at the phone distribution frame (the punch block thingy below the switch) confirms it. I don't know if those distribution frames are use elsewhere but are the standard way to terminate phone lines in Australia.

  • 1
    a 66 or 110 punch down block is what we typically use in the USA for terminating POTS lines. You'll see 66 block in older installations and 110 block in newer installations. – joeqwerty Aug 31 '10 at 1:37

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