Microsoft this week is announcing a big moment in the history of the company. No, this milestone does not involve Windows 10, Xbox, or Surface, but it is rather about telephones — and a full switch over to its very own Microsoft Teams collaboration software for internal company communications.

That’s right, Microsoft has publicly disclosed that come July 1st, 2019, it will be turning off the internal Private Branch Exchange (PBX) phone platform that is in use at its Redmond campus in favor of Microsoft Teams. In non-technical terms, this switch means that the complicated mix of switching centers, wires, repetitive backup systems, and thousands of physical phones, will no longer be in use. This same system also goes beyond just what employees need to make internal phone calls, and was needed for fire alarms, faxes, and customer service — essentials within the Microsoft campus.

That element of the PBX system was a key reason why the Redmond giant held onto it for a while, but according to Microsoft, it is no longer necessary. All normal internal user communications within its Redmond campus will now occur on Microsoft Teams. The company is replacing PBX and using third-party options to provide specialty communications solutions. External calls have been made outside the PBX system for quite some time via Lynx Servers, Skype for Business, and Microsoft Teams, and are will not be impacted by the change.

The journey to the “switch-off” from the aging PBX platform started about ten months ago after Microsoft’s CSEO team decided that it could help them get ahead if something could eventually go wrong with the system. The cost was also a factor, as according to Microsoft, the company spent over $40 million on wires, and $200 per phone installed on the PBX system.

Things even grew even more expensive, as Microsoft expanded from just 6,000 employees when the system was first installed to 79,000 in 2007. Other factors in the decision include the fact that the system was becoming antiquated, and challenging to support. In the words of Dwight Jones, Senior service engineer in Microsoft Core Services Engineering and Operations (CSEO.)

“This has been a highly reliable solution that has held us hostage for a long time. We are paying more than $1 million per year to keep it running … We’ve had to stay on this old system all these years because we needed it for our specialty services like fire alarms, faxing, calling corporate operators and customer service, and so on…”

To assist in turning off and decommissioning the internal PBX platform, Microsoft enlisted the help of National Communications Services, Inc (NCS.) This partner is both proficient in the old PBX system and shows expertise in Microsoft’s current communications technologies and software. “We have external customers that we have migrated to Microsoft’s modern communications platforms, like Teams, For every customer that we have migrated or moved, it has positively impacted their business process and overall success through improved communication and collaboration capabilities,” said Dan Trimble, who is a business development manager at NCS,

As Microsoft Teams continues to grow in popularity, many others could learn from Microsoft’s switch to modern communications. Teams is already in use at half a million organizations around the world, a showcase for the potential of transforming the workflows of employees everywhere.