Allied Telesis AT-AR042, AT-AR040-10, AT-AR041-00 manual AT-AR048 NSM, DS3 Interface

14 Network Service Module

AT-AR048 NSM

The AR048 NSM provides a single unchannelised DS3 interface with two BNC connectors for transmit and receive. The front panel of the AT-AR048 NSM is shown in Figure 9 and the functions of the LEDs are described in Table 4.

Figure 9: AT-AR048 NSM

RXTX

LOS

LOF

Loop

AIS

Activity FERF

Table 4: AT-AR048 LEDs

LED	State	Function
Active	Green	Lit when the Line Interface Unit (LIU) is receiving a signal.
Loop	Green	Lit when any loopback is active.
LOS	Amber	Lit when the received signal is lost. This usually indicates a network
		disruption, such as a cable being disconnected or a device failure.
LOF	Amber	Lit when the DS3 framer cannot extract valid frames from the
		received signal.
AIS	Amber	Lit when an Alarm Indication Signal is detected.
FERF	Amber	Lit when a Far End Receive Failure signal is detected. This indicates
		the far end is receiving an AIS, LOS, or LOF signal.

DS3 Interface

The AT-AR048 NSM provides a single standards-based unchannelised DS3 interface. The interface has the following features:

■44.736Mbit/s interface rate, 44.210Mbit/s payload data rate

■Separate transmit (Tx) and receive (Rx) BNC connectors

■75Ω impedance

■B3ZS line encoding

■Automatic compensation for lines up to 135m (450feet)

■Loop or internal timing

■C-bit framing

■Support for PPP and Frame Relay encapsulation

The interface meets the following specifications:

■ANSI T1.103, Digital Hierarchy - Synchronous DS3 Format

■ANSI T1.107, Digital Hierarchy - Formats

■ANSI T1.231, Digital Hierarchy - Layer 1 In-Service Digital

■RFC 2496 (DS3 MIB)

C613-03022-00 REV K