Analog Code:FIC_02RV2.T_2-wire loop reverse battery signaling/ loop closure from customer/ reverse battery from LEC/ 600 ohms. Used for Direct Inward Dialing
Digital Code:FIC_04DU9.1SN_4-wire 1.544 Mbps (DS1) with ESF/ Bipolar with Eight-Zero Substitution
EUT STD:47CFR68.316_Hearing aid compatibility: Technical requirements.