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Hardware overview
13
Model 3120 RAS Getting Started Guide
1 • Introduction
Hardware overview
The Model 3120 RAS is a fully integrated remote access server for central site concentration of analog and dig-
ital modem calls. The RAS (see figure 2) comprises a 1U-high 17-inch wide chassis that contains a mother-
board and two removable dual-redundant power supplies. A full set of LEDs are present on the chassis front
panel, while connections for WAN, LAN, and control ports are present on the rear of the chassis. Two IEC-
320 receptacles provide for AC power input. Optional DC power supplies with 32 to 72 VDC are available.
Figure 2. Model 3120 RAS features (
Cool White
version shown)
WAN
The RAS includes four WAN ports, each of which is software-selectable for T1, E1 or PRI operation. These
WAN ports are provided via balanced RJ-48C interfaces. They also include:
– Built-in T1/E1 CSU/DSU
– T1 1.544 Mbps with: D4 or ESF framing, AMI or B8ZS, FCC part 68 compliant
– E1 2.048 Mbps with: Double frame or CRC4 framing, AMI/HDB3, CTR-4, and CTR-12 compliant
– Surge resistant time-lag fuse has a rated current of 500 mA and a rated voltage of 250 VDC
LAN
The dual 10/100-Mbps Ethernet LAN ports are presented on an RJ-45 connector with an auto-sensing/full-
duplex 10Base-T or 100Base-T interface. It also includes:
– 100Base-TX half-/full-duplex operation (100 + 100)
– 10Base-T half-/full-duplex operation (10 + 10)
– Auto detection and fallback
– 10/100 Mbps link and status indicators