VDSL2 modem with profile 17a bonding / 35b single line bridge The Zyxel VMG4005-B50A is a VDSL2 modem that supports Profile 17a Bonding and 35b Single Line Bridge. This enables the maximum transmission speed of VDSL2. The VMG4005 is a high-end modem that achieves up to 200 Mbps with 17a bonding or 300 Mbps with 35b single line.