A Modem Sharing Device (MSD), also commonly known as a Line Sharing Device (LSD), modem sharer, or line sharer, allows multiple devices to share a serial connection. Only multipoint serial protocols such as bisync are supported. Both synchronous and asynchronous datastreams can be used. A common example would have a Tandem as host connected to multiple Automatic Teller Machines often with a modem or Cisco router in-between.
