6100 BSC Programming Manual

6100 BSC Link and Station Management
WRITE State
A station is in WRITE state when writing data, and whenever
it may write data, i.e., between WRITE requests or when
the other station allows a conversational reply.
TRANSITIONS TO WRITE STATE. The following events cause a station
to be in WRITE state:
• The application makes a WRITE request to make a line bid and
send the first message. During data transfer, the station
remains in WRITE state most of the time.
• The application makes a WRITEREAD request to send a
conversational reply. Although the station was in READ state
before the WRITEREAD request, it may change role when it sends
the conversational reply. If the other station responds with
ACK 0 or ACK 1, this station is in WRITE state. If the other
station responds with text, this station remains in READ
state.
• The application makes a CONTROL request to send a TTD
sequence. The station remains in WRITE state, although it
isn't ready to transmit a message.
TRANSITIONS FROM WRITE STATE. Transitions from WRITE state to
other states occur during every protocol transaction. The
following events leave a station in some other state upon their
completion.
• The application makes a WRITEREAD request to transmit a
message and accept a conversational reply. Although the
station is in WRITE state while transmitting the message, it
may change role when it accepts the conversational reply. By
using a READ request to send an ACK 0 or ACK 1, the station
enters READ state; by using a WRITE request to send text, the
station remains in WRITE state.
• The application or the remote station sends an EOT sequence.
The state changes to CONTROL.
• The application or the remote station sends a disconnect
sequence (DLE EOT), a modem failure causes DSR to drop, or the
application makes a STOP request. The state changes to
DISCONNECTED; BSC reports an error to the application.
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