[TenTec] Orion 2 Headphone RFI Filter

["Doug Turnbull" <turnbull@net1.ie>]

I have a friend who is purchasing an Orion 2 from another EI ham this week.
Can anyone tell me at what serial number TT first introduced the headphones
RFI filter?   I installed one in my radio eighteen months or two years ago.
I do not know the exact age of this radio but want to insure that EI2JD is
fully sorted.    73 Doug EI2CN