HDMI cables are OK for short distances but when you need to send an HDMI signal over a long distance or through walls it's often better to use an HDMI extender that uses CAT5e or CAT6 cable. An HDMI balun on either end converts the signal to one that can be sent over CAT cable and then back again at the other end.
HDMI extenders using CAT5e or CAT6 with baluns break the limit of normal HDMI cables and can reach over 120 meters or over 400 feet with quality cables and baluns.
HDBaseT HDMI Baluns
Special HDMI baluns that use a technology called HDBaseT can send HDMI audio and video over CAT5e or CAT6 cable through a network switch. It can be part of the existing network or its own standalone confguration. This allows one to many distribution in meeting rooms, bars, conference rooms and the like.