A small round connector for accepting the pin-shaped plug from certain phone headsets. This connector can be also be used with certain other types of accessories. While 2.5mm was the original ...
2.5mm jack curly clable with Plx QD "Works with Ciso SPA Series and other Cordless phones with 2,5mm Standard Headset Port.(3 poles with 2 black bands), No Smart phone use. Works with Grandstream ...