Xiamen Cai 2 F, 37#, Wangh Caimore RTU SDK Introduction Xiamen Caimore Communication Technology Co., Ltd 2 F, 37#, Wanghai Road, Xiamen Software Park 2, Xiamen, China Telephone: 0592-5902655 Fax: 0592-5975885 Zip Code: 361009 Website：www.caimore.com www.caimore.com.cn Email: caimore@caimore.com  Copyright Reserved 2014-2019 ----才茂通信 通畅天下 ---- Tel:+86 592 5901215 1 Web: www.caimore.com/emain.asp Xiamen Cai 2 F, 37#, Wangh Copyright: All information in this user manual is protected by copyright law. Whereby, no organization or individual shall copy or reprinted the whole or part of this user manual by any means without written authorization from Xiamen Caimore Communication Technology Co.,Ltd. Trademarks : Caimore, & CAIMORE are all registered trademarks of Xiamen Caimore Communication Technology Co.,Ltd. Other trademarks mentioned in this manual belong to other organizations related. Xaimen Caimore Communication Technology Co.,Ltd does not own the right of other trademarks and logos. Notice: Due to product updates or functional upgrading, we may renew the content of this file, and this file only for reference. All the statements, information, recommendations, etc. in this file do not compose any form of guarantee and we Caimore reserves the right of final explanation. Update Record: Version Date Modify Check V1.0.0 V1.0.1 Mark status First draft 2012-5-11 Tel:+86 592 5901215 2 Web: www.caimore.com/emain.asp Xiamen Cai 2 F, 37#, Wangh V1.0.2 2013-9-12 Catalog  Copyright Reserved 2014-2019........................................................................................................1 Catalog............................................................................................................................................................3 RTU Interface Communication Protocol..............................................................................................5 1. Protocol layered structure..........................................................................................................5 1.2 Link layer........................................................................................................................................6 1.2.1 RS-232 interface.............................................................................................................6 1.2.2 RS-485 Interface.....................................................................................................................6 1.2.3 GPRS mode...............................................................................................................................6 1.2.4 Ethernet mode.........................................................................................................................6 1.3 Acess layer....................................................................................................................................7 1.3.1 接口层协议 A（IP：A）..............................................................................................................7 3.3.2 接口层协议 B（IP：B）..............................................................................................................9 3.4 网络层..............................................................................................................................................11 3.4.2 网络层协议 A（NP：A）..........................................................................................................11 3.4.2.1 地址单元..........................................................................................................................11 3.4.2.2 通信包标识号..................................................................................................................11 3.4.2.3 分包数量..........................................................................................................................12 3.4.2.4 分包序号..........................................................................................................................12 3.4.2.5 NP 层交互标志................................................................................................................12 3.4.2.6 应用协议标识（APID）的规定....................................................................................12 3.5 应用层协议 RTU-A（AP：RTU-A）....................................................................................13 3.5.1 命令标识...........................................................................................................