HANDSHAKING AND RETRAIN INDICATOR
On the U-1496E, the HS LED will flash 1/2 second on and 1/2 second off to indicate that modem
is in handshaking or retrain.
EYE PATTERN GENERATOR
The Eye Pattern Generator (EPG) is a diagnostic tool used with an oscilloscope to evaluate the
telephone line or modem receiver performance. The EPG converts the signal received over the
telephone line to voltage signals that the oscilloscope displays as an 'eye' pattern or
'constellation' pattern.
Note: EPG is available only on U-1496 upon special request. Commercial model U-1496 product
does not include EPG.
You can diagnose telephone line problems by noting if the eye pattern on your oscilloscope is
distorted. The quality of the line depends on the area (country), weather, the route of each call,
and equipment, etc.. If the modem cannot resist the distortion, it will retrain or fall back to a lower
rate if the modem is configured this way.
To see the eye pattern, connect one oscilloscope probe to the X-pin and one probe to the Y-pin
on the rear panel of the modem. Connect the ground of each probe to the G-pin. Put the
oscilloscope in XY mode. The modem speed standard determines the number of points in the
eye pattern.
RESETTING THE MODEM
If you change the modem's setting and cannot get it back, or you just want to get back to the
factory default state, the following reset procedure will reset the modem to the factory state. On
the U-1496E and U-1496B, this procedure also makes the modem run a self test. It is a good
way to test the modem hardware.
On the U-1496, holding the ENTER key down for a few seconds while powering up will reset the
modem.
On the U-1496E, holding the VOICE/DATA key down for a few seconds while powering up the
modem will reset the modem. The modem will also run a continuous analog loopback self-test.
Printable characters will be shown on the terminal connected to the modem's RS232 port. The
HS, CD, DSR, CTS, RXD, EC, SQ, and TST LEDs should be ON. If not, there is a hardware
problem. Contact the nearest service center for help. If SQ flashes, the number of flashes
indicates the error number corresponding to the error message listed at the beginning of this
chapter.
On the U-1496B, short the TS2 jumper with a plug then power up the computer. The modem will
be reset and will continuously run a self-test. Printable characters will be shown on the computer
screen. The TS1 LED should be continuously ON. If the LED flashes, the number of flashes
indicates the error number corresponding to the error message listed at the beginning of this
chapter.
FIRMWARE UPDATE
