sercd is an RFC2217-compliant serial port redirector. It lets you share a serial port through a network. It is based on sredird. The RFC2217 protocol is an extension to telnet and allows changing communication port parameters.
Sredird is a serial port redirector that is compliant with the RFC2217 "Telnet Com Port Control Option" protocol. This protocol lets you share a serial port through the network. RFC2217 was orginally implemented in Cisco Terminal Servers in IOS version 11.x.
cyclades-serial-client is an RFC2217 compliant client that works with servers such as Cyclades Terminal Servers and sercd. It creates a virtual serial port which connects to the server over a network.