Bay Technical Associates 529H - Manual (Page 24)

 
  
In Mode of Operation 5, a single message is sent to the host port from
a selected peripheral port. Operation in Mode 5 enables the host
device to receive one complete message from a selected peripheral
port by sending the control character followed by ASCII capital
S and
the desired port number (1 to 4 for the 525H, 1 to 8 for the 528H and
529H, and 01 to 17 for the 5218H). If no message is available, the
host port will transmit a
Carriage Return/Line Feed.
NOTE: The host device may select and transmit data to any
peripheral port while simultaneously receiving single messages from a
specific peripheral port.
 
  
Mode of Operation 6 provides time-division multiplexing. The internal
processor in Mode 6 continuously scans all peripheral ports checking
for characters in the receive buffers. If a receive buffer contains
characters, the characters are transmitted through the host port
preceded by a port identification code which consists of the control
character followed by the peripheral port number. Transmission
continues until the buffer is empty or until a user-defined maximum
data block length has been transmitted. After transmission is
completed, the multiport will continue its scanning sequence.
If a control character is received by the multiport from a peripheral
device, a second control character is added automatically. This
technique allows you to detect the control character as a data
character when it is sent through the multiport.
NOTE: The host device may select and transmit data to any
peripheral port while simultaneously receiving data blocks from all
peripheral ports.