NAME

st − synchronous terminal interface

DESCRIPTION

The synchronous terminal interface is a pseudo-device driver that enables a UNIX system to communicate with a TELETYPE® Model 40/4 ASCII synchronous terminal.  The driver utilizes the Virtual Protocol Machine (VPM) to perform the end-to-end protocol and transmission assurance for the synchronous line. 

The user must be familiar with the operation of the Model 40/4 terminal.  Screen management functions are completely controlled by the user process; when formating a screen, the user must supply everything from the initial STX (Start-of-Text) character to the ETX (End-of-Text) character. 

By convention, /dev/st0 is the synchronous terminal control channel, while other /dev/st?  files represent user terminal channels.  Communication with the control channel is handled by the stcntrl command (see st(1M)).

A user process will sleep when trying to open a channel, until a terminal requests service.  At that time, a channel will be assigned to that terminal, and it will remain allocated until the user process closes the terminal. 

In addition to the synchronous terminal equipment, a KMC11-B microprocessor, and a DMC11-DA synchronous line unit are required. 

FILES

/etc/stproto synchronous terminal prototype script

/dev/kmc?  KMC11-B microprocessor

/dev/vpm?  virtual protocol machine

/dev/st0 synchronous terminal control channel

/dev/st?  synchronous terminal user channels

SEE ALSO

st(1M), kmc(4), trace(4), vpm(4). 

May 16, 1980