User`s guide

6: ADCCP NRM Line-Monitor Function
DC 900-1317J 113
usFiller[2]: This field of the Monitor Data Notification header rounds out the first 12
bytes. It contains 0s.
Abstract: This field of the Monitor Data Notification header contains a 12-byte
abstract of the associated frame contents. The frame abstract is rendered as a “C”-lan-
guage structure in Figure 6–2. Its fields are described next.
usAddress[4]: This field of the Frame Abstract contains the frame’s Address field con-
tents. Single primary and secondary station addresses may occupy up to four bytes.
When the Address field occupies fewer than four bytes, the remaining bytes of this
Frame Abstract field contain zeros to indicate their non-use. However, a series of selec-
tive broadcast addresses may occupy up to 32 bytes, in which case only the first four
such bytes are stored in the Frame Abstract. To obtain the rest of the Address field bytes,
the client program must examine the frame image.
cAddrType: This field of the Frame Abstract contains the frame address type. This may
be Local, Remote, Global Broadcast, or Selective Broadcast, as indicated by an ASCII
’L’, ’R’, ‘G’, or ‘S’.
typedef struct {
unsigned char usAddress[4];// address field
unsigned char cAddrType; // ‘L’, ‘R’, ‘G’, ‘S’
unsigned char usFrameID; // frame ID (see below)
unsigned short usILen; // length of I-field
unsigned char usNS; // N(S) value (0-127)
unsigned char usNR; // N(R) value (0-127)
unsigned char cPF; // P/F bit (0 or 1)
unsigned char usFCS[2]; // FCS value (recv’d frames)
} FRAME_ABSTRACT; // total of 12 bytes
Figure 6–2: Frame Abstract