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ASM-20 Installation and Operation Manual Chapter 1 Introduction
Physical Description 1-3
• Built-in Ethernet bridge.
Connection to an RS-449/V.36 interface is accomplished via the RS-530 interface
(see Appendix A, Ethernet Interface). ASM-20 incorporates a built-in Bit Error Rate
Tester (BERT). The internal BERT allows complete testing of both modems and the
line without external test equipment. A front panel switch generates a pseudo-
random test pattern (511-bit, according to ITU/V.52) for testing end-to-end
connectivity. The ERROR LED will flash when a bit error is encountered.
1.2 Physical Description
ASM-20 is available as a desk-top unit or a rack-mountable card for a 19" rack.
The rack can carry up to 14 ASM-20 cards which provide a 25-pin
D-type connection to the digital interface. Optional interface adapters for V.35,
X.21, G703 and ETH are available. The ASM-20/R card can detect and indicate
power failure on the remote ASM-20 standalone unit. The RPF LED will light up if
remote power failure occurs.
Front Panel
Figure 1-4 shows a general view of ASM-20.
Figure 1-4. ASM-20
LEDs
All controls (push button and LED indicators are located on the ASM-20 front
panel (see Figure 1-4). A description of the front panel can be found in Controls
and Indicators in Chapter 3.
Jumpers
A description of the jumpers can be found in Setting Internal Jumpers and Switches
in Chapter 2. See Table 2-1 and Figure 2-3.
Rear Panel
Figure 1-5. ASM-20 Rear Panel with V.35 Interface