CSE-H21 User’s Manual Ver. 1.2
Sollae Systems Co., Ltd.
- 35 -
http://www.sollae.co.kr
5.3
COD
In COD mode, the ezTCP functions as a client.
When data of the pre-specified size [Byte Count] comes to the serial port, the ezTCP attempts a
TCP connection to the TCP port [Peer Port] of the preset host IP [Peer IP Address]. If the remote
host accepts the TCP connection, TCP connection will be established. Data coming to the serial
port after connection establishment is TCP/IP-processed and transmitted to the remote
host. And, data coming from the remote host is TCP/IP-processed and transmitted to the serial
port for data communication.
Remote Host
Serial Device
ezTCP
Listen
Request TCP c
onnection
Accept TCP connection
DATA
“
AB
”
DATA
“
DEF
”
DATA “ABC” (TCP/IP)
DATA
“
GHI
”
(TCP/IP)
DATA
“
GHI
”
connected
<COD connection sequence
–
Byte Count: 3>
Remote Host
DATA
“
C
”
Ack
DATA
“
DEF
”
(TCP/IP)
Figure 5-2 COD Mode
5.3.1 Serial Data Before the TCP Connection
If the [Byte Count] is 0, all data from the CSE-H21‟s serial port before the TCP
connection are ignored. If the [Byte Count] is over 0, CSE-H21 stores serial data to its
memory and it transmits these data when CSE-H21 is connected.
5.3.2 Data Transmission
Once TCP connection is established, hosts can communicates with the CSE-H21 bi-
directionally. And CSE-H21 gathers data from its serial ports. It transmits data when there‟s
no data during the specified in the [Guard Time]. If the [Guard Time] is 0, it transmits as
soon as it receives data from the serial port.
The unit of the [Guard Time] is 10ms. And minimum time is 40ms so minimum guard
time is 4(except 0).
