Panasonic and American telephony is like a Japanse Sister City. Instead of giving a city in America thier cherry trees, Panasonic is known by consumers (Esp Boomers) for their cordless telephones that was popularized in the 1990s. But at the same time for businesses under 20 extensions or a dozen more, their KX-T series was popular. Panasonic got out of the phone system business in the mid 2020s, but gave signals to the Federal Communications Commission in 2019, filing the only opposition to the Kari Hunt Law warning the FCC that installers may take early retirement because stakes can be so high that installers could be sued. The FCC only listened to Avaya and well the FCC and Avaya killed enterprise voice when the law was forced to be in compliance in early 2020. It's important to show their mark. The KX-TD 500 was one of the couple large PBX systems that supported multi carrier cabinets with hundreds of extensions.