D-Link 12-Port Optional Module Internal 0.1Gbit/s network switch component

12-Port Optional Module for DES-6000 Features:
(12) 100BASE-FX (MT-RJ) Fast Ethernet ports
Fully compliant with IEEE 802.3u 100BASE-FX
Back pressure Flow Control support for Half-duplex mode
IEEE 802.3x compliant Flow Control support for Full duplex
Per port packet buffer: 0.5 Mbytes
Supports multi-mode fiber-optic cable connections of up to 412 meters in half-duplex or 2 km in full-duplex mode.
Connects to 100BASE-FX devices at full- or half-duplex.