This AJA HA5 converter is a great tool for video and audio conversion from HDMI to SD/HD - SDI. Note that it doesn't come with a power supply.

To use this AJA HA5 HDMI to SD/HD - SDI converter, first connect your HDMI source device to the converter's HDMI input. Then connect the output of the converter to your SD/HD - SDI device. Since it doesn't have a power supply, you need to use your own suitable power source. When using, make sure all connections are secure. For maintenance, keep it in a dry and clean place. Avoid exposing it to extreme temperatures or moisture. If there are any issues, check the connections first before seeking further help.