Installation guide

92 DC 900-1564A
Synchronous Link Control (SLC) Programmer’s Guide
6.4.3.5 Additional Characteristics Indicator (ACI)
The additional characteristics indicator field is optional in each SLC message sent and
received on a high-level SLC network. If the
LCI_ACI_PRESENT bit is set in the lci field,
then the ACI is present, and is inserted between the
mci field and the info field shown
in Figure 6–2 on page 89. When present, the ACI and any ACI Extensions do not reduce
the maximum message length. Table 6–5 shows the internal format of the
aci field; each
extension of the ACI has the same format.
Table 6–5: Additional Characteristics Indicator (ACI) and Extensions on
High-level Networks
Additional Characteristics Indicator (ACI) — One character per ACI or ACI Extension
ACI_BASE_VALUE Always set
ACI_EXTENSION Extension of ACI present when set
ACI_CONTENT_MASK Mask to isolate (&) or ignore (&~) undefined portion of ACI