Northern Telecom DMS-100 Series Installation And Maintenance Manual page 98

0 297-2121-226
0 VINTAGE 05.01
0 10. Press the Settings key.
0 turn off.
0 11. Press the Alternate key.
0 To Perform a Tip-and-ring Loopback Test:
0 1. Press the Settings key.
0 2. Press the Alternate key.
0 3. Press the
0 Loopback LED lights.
0 4. Press the Settings key.
0 Under Test LED lights.
0 5. Type a
0 typed characters are echoed back to the terminal, the channel
0 between the DU and the DTE, and the DU circuitry is good.
0 6. Press the Settings key.
0 7. Press the 0 on the numeric keypad until none of the
0 LEDs are lit.
0 8. Press the
0 turn off.
0 9. Press the Alternate key.
0 To Perform a Tip-and-ring Loopback Test:
0 1. Press the Settings key.
0 2. Press the Alternate key.
0 3. Press the 5 on the numeric keypad until the Tip-and-ring Loop
0 LED is lit.
0 4. Press the Settings key again.
0 the Under Test LED lights.
0 5. Type a string of characters on the
0 typed characters are echoed back to the terminal, the channel
0 between the DU and the DTE, and the DU circuitry is good.
0 6. Press the Settings key.
0 7. Press the 5 on the numeric keypad.
0 LED turns off.
0 8. Press the
0 turn off.
0 5-8
The Settings LED lights.
0 on the numeric keypad until the Tip-and-Ring
The Settings LED turns off
string of characters on the DTE keyboard.
The Settings LED lights.
Settings key.
The Settings LED lights.
The Settings LED lights.
Settings key.
The Settings and
The Alternate LEDs turn off.
(NT4X25AF /AH)
The Alternate LED lights.
The Settings and Under Test LEDs
The Alternate LED turns off.
(NT4X25AG /AK)
The Alternate LED lights.
The Settings LED turns off and
DTE keyboard.
The Tip-and-ring Loopback
The Settings and Under Test LEDs
Under Test LEDs
and the
If the
loopback
If the