VoIP phone teardown

-January 25, 2017

Look inside a ShoreTel 230 VoIP telephone from 2011 – my old home-office phone.

The phone, about to encounter a destructive teardown, because…parts.

The “pental” feature at the bottom left is not a foot, but the hands-free microphone. Is it trying to be a pressure-zone mic?

The main board; common-mode toroids on the audio-jack wire connections.

Closer in. Broadcom BCM1104 (product brief) dedicated IP phone chip (dating back to 2005, but still active) & BCM5482 gigabit Ethernet transceiver. Spansion 29GL064N90 64Mb 90ns NOR Flash. Samsung K4H561638 16M×16 DDR SDRAM. I’m willing to bet that the resistors and serpentines do more harm than good in such a simple hookup. All those RCs up top are on the ribbon-cable lines going to the LCD & button board. EMI reduction?

I see no indication that the LCD was made by an LCD specialist manufacturer, which makes the COB (chip on board) construction somewhat surprising. But who knows…

The LCD board, with elastomer buttons and multi-coloured LEDs.

Main board bottom side. The bridge rectifiers are for the 48VDC proprietary(?) PoE inputs, perhaps protecting against connection of a different proprietary adapter!

Love the engineered, well-sealed speaker enclosure (or maybe it’s just for maximum mic isolation).

I’ve seen lots of speakers in my day, but never one like this. I’m no magnetics expert, but does the top magnet do anything?

You’ve gotta love the fine molded filigree webbing holding and springing the buttons.

I stopped using this phone when the system/network reliability became too poor (it was always pretty poor come to think of it). The IT people said the ping time to the New York City server had to be under 100ms, and it wasn’t always so. Considering I could get shorter pings to the other side of the planet, I’ll let you draw your own conclusions about that NYC server.

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