User`s guide

62 DC 900-1317J
ADCCP NRM Programmer’s Guide
broadcast addressing is indicated. If bit 1 is reset to zero and bit 2 is set to one, general
broadcast addressing is indicated. Bit 0 and bits 3 through 7 in the
iProtModifier field are
zeroed.
3.4.10 DLI_PROT_SEND_UNNUMBERED_DATA Packet
This packet is valid only if the client has enabled ADCCP option 4 (see Section 3.4.20.2)
for the specified station. The client must specify the
usProtCommand field
(
DLI_PROT_SEND_UNNUMBERED_DATA), the iProtModifier field, the usProtXParms[0] field (sta-
tion ID), the
usProtXParms[1] field (data size), and the data field contents.
For NRM stations, bit 0 in the iProtModifier field indicates whether more data follows.
The client should use the more data indication if one of the following conditions
applies:
• The client sends numerous Unnumbered Data packets via an NRM primary sta-
tion using selective or global broadcast addressing and wants to use RNR polling
instead of RR polling to inhibit secondary response I-frame transmissions during
the broadcast
• The client wants to send as much data as possible in each poll response via an
NRM secondary station
When bit 0 in the iProtModifier field is reset to zero, the ICP assumes that the data packet
is the final frame in a data set. If the data packet is sent via an NRM primary station, the
ICP enables normal polling. If the data packet is sent via an NRM secondary station, the
ICP transmits the data in an I-frame with the F-bit set to one.
When bit 0 in the iProtModifier field is set to one, the ICP assumes that more data pack-
ets follow. If the data packet is sent as part of an NRM primary station broadcast, the
ICP switches to RNR polling (to inhibit secondary response I-frame transmission) and
allows the client one to two seconds after broadcast completion to send more data
before reverting to normal (RR) polling automatically. If the data packet is sent via an