Analog Firewall Model FWA101H / TSG 5S0204Analog Firewall Model FWA101H TSG 5S0204 DATA SHEET Analog Firewall TSG Approval Is a US Government approved (NSA Labs) secure telephonic Disconnect Isolation device for use with ALL analog tip and ring devices (phone, fax, modem, teleconference) requiring full time protection and active countermeasures from unauthorized listening and acoustic monitoring during any On Hook condition. Sound masking: White noise machines and noise generators to correct