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ASM-20 Installation and Operation Manual Chapter 4 Troubleshooting and Diagnostics
Local Test - Analog Loopback 4-3
4.3 Modem Self Test
The modem self test verifies that ASM-20 is operating correctly.
To verify that ASM-20 is operating correctly:
1. Press the ANA (Analog Loopback) push button on the front panel. Both the
TEST and DCD LEDs should light up. If the DCD LED does not light up, check
that the CARRIER jumper is ON or that the RTS signal is ON (high).
2. Press the PATT push button. Verify that:
DCD LED is still lit up
TEST LED is still lit up
ERR LED lights up for a short period.
The ERR LED should then turn off. If it lights up or blinks, then ASM-20 is
faulty and should be replaced. If the test executes correctly, restore all the
push buttons and jumpers to the required position.
4.4 Local Test - Analog Loopback
This test checks the performance of the local modem, the local data terminal and
the cables connecting them. Perform it separately at the local and remote sites.
ANA
Pressed
LINE
ASM-20
XMTR
RCVR
DATA
TERMINAL
CLK
CLK
DATA
Figure 4-3. Local ASM-20 in Analog Loopback
To check the performance of the local modem and the local data terminal:
1. Press the ANA (Analog Loopback) push button on the front panel (see
Figure 3-1). This test can also be activated via the pin on the DTE interface.
See Table 2-2 for more information. The TEST LED should turn on. ASM-20
transmit output is now connected to its own receiver (see Figure 4-3).