Manual

Introduction 1-5
1.2 SECS-II Clarifications
The GES-1993 uses the following SECS-II conventions:
1.2.1 Data Format Types
Where the Standards permit a choice of data item types, the choice has been made as
described in section "Message Detail".
For outgoing messages, the Equipment always sends Data Items of the exact format
shown. For some incoming messages, the Equipment "forgives" minor host errors.
For example, the Equipment may accept a U1 Data Item where a U2 format was
expected. We recommend the Host attempt to use the formats shown.
1.2.2 Data Item Length Bytes
For messages sent by the Equipment, the number of length bytes in Data Items is
always the minimum required to contain the Data Item length.
For messages received from the Host, the number of length bytes in Data Items can
be 1, 2, or 3, provided that the length parameter can accurately be specified.
1.2.3 ASCII Data
Unless otherwise specified, all ASCII data items must contain printable ASCII data -
- that is, characters in the range 0x20 to 0x7E.
1.2.4 Multi-Block Messages
Wherever the Host is supposed to send a single-block message, this Equipment will
also accept multi-block format.
The maximum size for a single SECS message is approximately 1000 blocks
(256,000 bytes).