A:
Hi Jerry, Unfortunately, the H600 Wireless Headset isn't RJ9 compatible, even when using an adapter. Your best bet would be to use a wired headset, like the H390 and use an adapter like this one: https://www.amazon.co.uk/Female-Telephone-Phone-Connector-Adapter/dp/B071DF3BFJ. Hope that this helped and hope you have a wonderful weekend. - Richard from Logitech