USB - PTT support

Corded USB - PTT

• SHS 2371-11: USB - PTT, Stereo (P/N.: )
• SHS 2371-12: USB - PTT, Stereo, Serial Number embedded (P/N.: )
• SHS 2355-11: USB - PTT, Mono (P/N.: )
• SHS 2355-12: USB - PTT, Mono, Serial Number embedded (P/N.: )