Manual

1-4 Introduction
1.1.4 SECS-I Blocks Received
Blocks received by the Equipment should be formatted as described above (except
with the R-bit set to "0"), although the rules are more relaxed:
 If a message consists of a single block, the Block Number may be zero (0x0000)
or one (0x0001).
 The Equipment is indifferent to the R-bit setting.
1.1.5 Interleaved Blocks
The GES-1993 never sends interleaved blocks to the Host. That is, the Equipment
always sends all blocks of one message before sending the first block of the next
message. This simplifies the job of the Host.
However, the Equipment allows the Host to send interleaved blocks, if it so chooses.
1.1.6 Simultaneous Transactions
The GES-1993 may initiate several simultaneous outstanding SECS transactions.
That is, the Equipment may send a secondary primary message before the Host has
sent the Reply to a previous primary message. Mainly, this occurs when the
Equipment reports Alarms and Events. The Host can reduce the number of
outstanding transactions initiated by the Equipment by setting Equipment Constants
appropriately so that the Equipment sends no W-Bit for Stream 5 (Alarm), Stream 6
(Event), and Stream 10 (Free Text) messages.
The Equipment allows the Host to initiate at least two (2) simultaneous outstanding
transactions.