Line 1 has one IP phone service. Line 2 has Gizmo5. When I connect brother mfc845cw fax phone to line1 port. It can receive both line1 and line2 calls. When I connect this fax phone to line2 port, it only receive line2 call. The fax phone has 2-cord phone line, not 4-cord. It is not a 2-line phone. Thanks in advance!