3Com MSR 20, MSR 30, MSR 50 manual Following table describes the LEDs on the FIC-1AT3 panel

FIC-1AT3 187

■Four types of test measures: local cell loopback, local loopback, remote payload loopback, and remote line loopback.

n You may equip your router with FIC-1AT3 cards to its full capacity. Yet, you are recommended to install only one FIC-1AT3 on it, whatever its model is, to ensure performance of some key services.

Interface Attributes The following table describes the interface attributes of the FIC-1AT3.

Table 131 Interface attributes of the FIC-1AT3

Attribute	FIC-1AT3
Connector	SMB
Number of connectors	2
Interface standard	G.703, G.704, G.823
Interface rate	44.736 Mbps
Interface cable	E3/T3 cable (75-ohm coaxial cables)
Supported services	ATM Traffic CBR, rt_VBR, nrt_VBR, UBR

Interface LEDs The following figure illustrates the FIC-1AT3 panel:

Figure 229 FIC-1AT3 panel

The following table describes the LEDs on the FIC-1AT3 panel.

Table 132 LEDs on the FIC-1AT3 panel

LED	Description
LINK	OFF means no link is present; ON means a
	link is present.
ACT	OFF means no data is being transmitted or
	received; blinking means data is being
	received or/and transmitted.

Interface Cable The interface that the FIC-1AT3 provides uses two SMB sockets for data transmitting and receiving respectively. The ports adopt the 75-ohm unbalanced transmission mode and are connected to the peer device using a pair of 75-ohm unbalanced coaxial cables as shown in Figure 228. Several cable length options are available.

n The FIC-1AT3 and FIC-1AE3 cards use the same type of cables for connection, which are called E3/T3 cables in this manual.