Toshiba 3000 - TOSDIC-AD System Message Format

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5.8TOSDIC-AD System Message Format
5
5.8 TOSDIC-AD System Message Format
The TOSDIC-AD system uses messages in the LLC (Logical Link Control) data link
format shown in figure 5-17.
Figure 5-17 LLC Data Link Message Basic Format
The socket data header identifies socket data and commands or responses in the LLC-
data link format. Responses are used for command acknowledgment (ACK) in the LLC
communication procedure. The responses mentioned here mean response data sent and
received to and from a TOSDIC-AD system, and receiving a command is called response
in the LLC communication procedure.
Before sending and receiving commands and responses in the LLC data link forma
t, it is used as a message for registering service access points.
Auxiliary information indicates the transmitting source address of the command or
response received. The format is a combination of the upper and lower 8 bits of the class
C format of IP address (0xC001 to 0xC07F). Specify 0 for message transmission.
In sending a command, set a service access point in the destination service byte where
LLC-format messages will be sent or received. In receiving a response, the service
access point sent from the transmitting source is set.
Text size indicates the byte size of an LLC-format command or response.
Status indicates the state of processing an added message in case of response
messages. Status is unused for command messages, in which case 0 must be specified.
The value 0 indicates that the command has been processed normally and that a normal
response has been received. The value 2 indicates an error detected at the local station.
When the value is 2, an error code is set at the head of the response to show the cause
of the error. (Figure 5-18)
Command/
Response
15 0
Status
LLC-format command
or response
（n bytes）
+00(0x00）
+04
(
0x04
）
+06
(
0x06
）
+08
(
0x08
）
+10
(
0x0A
）
+12
(
0x0C
）
+14
(
0x0E
）
+16
(
0x10
）
Service access point （
DLSAP,・SLSAP
）
Byte address
Socket data header：
'AN712 P C L CM '
'AN712 PCL RS '
or
'AN712 PCL SP '
'AN712 PCL SR '
+20(0x14）
+22
(
0x16
）
Aux. Information （
transmit source address
）
+18
(
0x12
）
Text size （n bytes）