Tales along the way in my quest to Integrate Everything.

Salvaging a Cisco CP-7970G VOIP SIP Phone

I regularly scan the local electronics recycler for deals on last-chance electronic devices. I’ve run Asterisk for about a year on my home VOIP phone system, using a Linksys PAP-2T SIP to POTS converter, and it has worked flawlessly. However, there has been a flood of used IP phones on the Recycler’s web page of late, and one in particular caught my eye. This was a used Cisco CP-7970G SIP VOIP (Voice Over IP) phone, and a very nice one at that. The problem: It didn’t work.

As it turned out, this particular phone had a manufacturing defect in one of the connectors that joins the circuit board to which the ethernet cables are connected and the main PCB. During initial insertion, one of the tiny pins that joins circuits from one PCB to the other got misaligned, and the insertion force then broke off the pin. Being practically contained and with nowhere to go, the pin remained in almost the exact spot it needed to be, and in fact continued to conduct the electrons on their merry way, but even the slightest “tug” on any of the connected cables would create just enough of a gap that the circuit would be broken.

Some fine soldering on my part later and I had created an alternate path for those electrons, and removed the remnant of the pin from the connector. The result? A perfectly working SIP based Cisco VOIP phone with color touch screen and 8 line support – for the low, low price of one easy payment of only $39.95. (Said in my best infomercial voice.)

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