X25AM Programming Manual

PTP Applications
X25AM Programming Manual—527201-001
3-21
Mode 3
•
Call Request, Call Connected
•
Call Accepted, Incoming Call
•
Clear Request
•
Clear Confirmation (application READ only)
•
Clear Indication
The following SETMODE command enables pass-through mode:
SETMODE 31 param1.<1> = 1
Not all networks allow addresses in Clear packets.
Fast-Select Support
Fast Select is an optional user facility that allows extra data to be included in Call
Request, and Call Connected packets.
•
Call Request packets with fast select can be written and read with data- exchange
mode.
•
When fast select is used, the line should be configured for extended format, either
with the macro modifier EXTFORMAT, or the SCF line attribute EXTFORMAT. The
macro modifier must be used if PACKETSIZE is less than 256.
Mode 3
Your application can process data that goes into or comes from multiple data packets
or a single interrupt packet. Information for packets is written into or read from the file-
system buffer. The first word in the buffer is the MCW. The rest of the buffer contains
data or interrupt data.
Data appears in the file-system buffers as a block of data. This might be a logical
record or part of a logical record. For example, a logical record might consist of 4096
bytes. The block that is read and written might be 1024 bytes.
PTP disassembles blocks of data coming from the application into data packets and
assembles data from data packets going to the application into blocks of data.
A logical record can consist of data for or from one or more data blocks. Construction
of a logical record from data blocks is the responsibility of your application. The M bit in
the MCW determines whether the data in the buffer is the final packet for the logical
record.
Packet types and application buffer contents used for mode 3 are shown below.
Acceptable packets:
Data packets