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Communications Command
Caution
!
5-3-4 Special Read (RD): For I.CODE1 Mode Only
When there is only a single Tag in the communications area, this command enables to read data
from the Tag faster than a usual Read.
<Command Format>
Node No.. Command code
STX
1
2
Communications
method
Data type
Tag No. setting
First read page
No. of read pages
<Response Format>
STX
Node No..
1
2
Response code
Read data
From Page FD to Page FE is a system area for write-protect and
QUIET/EAS settings. Depending on the content of write data, a Tag may
become write-protected or inaccessible, so be sure to understand these
pages fully before use.
It is strongly recommended that you use a system command to write in
these pages (refer to 5-4) rather than using the write command.
Communi-
"RD"
cations
method
2
2
Specifies the communications method with a Tag.
UT: Special Read Trigger
UA: Special Read Auto
UR: Special Read Repeat
* For details, refer to 5-8 Communications Methods
Specifies whether the read data is represented in ASCII or HEX.
A : ASCII code
H : HEX code
* For details, refer to 5-9 Data Type
Set the number of Tags which communicate simultaneously.
* For details, refer to 5-10 Tag No. setting.
Specification range: 0 to 7
Specifies the first page in hexadecimal to read from the Tags.
Specification range: FB to 04h (when Block 4 for a Philips product is used
as the user memory, refer to 2-4 of Section 2 Memory Map of Tag)
Specifies the number of pages from which data is read in hexadecimal.
Specification range: 01 to 10
Retry
Command code
Response
"RD"
flag
code
"00"
1
2
2
00:normal completion
For other response codes, refer to 5-2-4 Response code List.
Indicates data having read from the Tag. The number of characters of the
data is as follows.
ASCII Code: No. of write pages x 4
HEX code: No. of write pages x 8
Note This Special Read (RD) Command enables you to read from multiple Tags,
however, unlike the read command (5-3-1) of multi-communications method,
this Special Read Command does not execute anti-collision processing (a
collision avoidance processing against the responses from a Tag). Thus
when a collision (conflict between responses) occurs, it will be unable to read
data from a Tag. To read data from a Tag, the host must retry Repeat Com-
mand. When there are a few Tags, the Special Read Command has an ad-
vantageous communication speed rather than multi-command does even if it
executes Retry processing. The command works in I.CODE1 mode only, and
ISO mode is not available.
Setting
No. of read
Data
First read
Tag
type
page
No.
1
1
2
Read data
As specified
ETX BCC
pages
2
1
1
ETX BCC
1
1
Section 5-3
5-15
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