Billion Electric Company BiPAC 8501/8521 - Manual (Page 75)

Billion BiPAC 8500/8501/8520/8521 SHDSL (VPN) Firewall Bridge/ Router
Chapter 4: Configuration
71
SHDSL – BiPAC 8521
Standard 4-wired connection: the 4-wired handshaking procedure that is compliant
with ITU-T standard.
False 4-wired connection: This mode is used when 4-wired connection is disabled.