My Modem Connection Hangs-Up Unexpectedly - evertz 8084 Instruction Manual

Models 8084/8084AD/8085 Closed Caption Encoder Manual
Port Passthrough echoes serial commands sent into one port back out of
another port (Port B specifically).
Using Port Passthrough, there is no feedback from the second encoder
receiving the serial commands. If a serial command is not valid for the
second encoder, no error message will be returned to the captioning
computer.
The serial protocol used for the VBI Bridge is not compatible with the Port
Passthrough modes. If one unit is configured for VBI Bridge operation and
the other for Port Passthrough, unexpected and erroneous operation will
result.
As a safety measure, the operator cannot place port B in Funct CC recv
mode if any other port is supplying the unit with captions to place in the SDI
video.

6.1.22 My Modem Connection Hangs-Up Unexpectedly

The following can cause unexplained hang-ups on a modem connection:
RAIN - If there has been any significant rainfall during this time, moisture
can get into the lines and cause power hums and other sorts of nasty
things to happen. This can cause the DC level of the phone line to vary,
which then modems can interpret as loss of carrier.
DISTANCE - If the captioner is quite a distance from the CO (Central
Office) where they are near the limit of transmission, dropouts can occur if
there is not a line booster in place. If there is a line booster, this can also
be a problem if there are grounding issues, etc.
CAPTIONERS MODEM - If the initialization string is setup incorrectly, this
can cause the modem to not function correctly. They may want to check
the modem manufacturer for the recommended set-up for they're particular
modem so it is capable of operating in the 1200 to 2400 baud range. Some
people that use US Robotics 56.6k modems have reported difficulties
connecting at lower baud rates due to these setup strings.
OTHER SOFTWARE - If there is any other software on the system that
uses the modem, it may have changed the initialization string or be
interfering with the modem. On computers that use a COM-port mouse, the
mouse may also interfere with the modem operation if it is configured
incorrectly.
READ THE MANUAL - Be sure the captioner knows their system inside
and out. They should at minimum, be able to supply what their system
configuration is.
TROUBLESHOOTING Page 6-9
Revision 1.6.6