A scrying mirror is a mirror that allows someone to see and hear sights and sounds at a different location. In particular, scrying mirrors can connect to other scrying mirrors, allowing people from either end to hold conversations. When not used in this way, it behaves as a normal mirror.
Scrying mirrors are typically installed in places such as meeting rooms or dining rooms where people often gather. In order to operate, mirrors require an active connection to a source of mana, such as a ley line.
When a magician wishes to use a scrying mirror, they stand in front of it and use their mana to form a specific pattern corresponding to their target location. If the location is another scrying mirror, then a person on the other end will be able to sense magic from their mirror and can choose to connect back to the originating mirror.
If the person on the other end is currently connected to a different mirror, then interference is caused, resulting in a disruption in the connections for all scrying mirrors. After a connection is established, disconnecting requires either end to stop supplying mana to the mirror.