发明名称 |
PACKET DATA COMMUNICATION SYSTEM |
摘要 |
PACKET DATA COMMUNICATION SYSTEM ***** A packet data transmission system is used to link a number of remote handheld data-gathering units such as bar code readers to a central computer which maintains a database management system. Data packets are sent from the remote units by an RF link to intermediate base stations, then sent by the base stations to the central computer by a seal link. Direct sequence spread spectrum modulation is used for the RF link. The remote hand-held units initiate an exchange using RF transmission to and from the base stations, receiving only during a rigid time window following a transmission from the remote unit. The base stations cannot initiate communication to the remote units, but instead send data to the remote units only as part of the exchange. 66
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申请公布号 |
CA2072345(A1) |
申请公布日期 |
1993.05.28 |
申请号 |
CA19922072345 |
申请日期 |
1992.06.23 |
申请人 |
SYMBOL TECHNOLOGIES, INC. |
发明人 |
TYMES, LAROY;KRAMER, JOHN W., JR. |
分类号 |
G06K7/00;G06K17/00;H04B1/707;H04L5/14;H04L12/28;H04L12/56;(IPC1-7):H04L12/56 |
主分类号 |
G06K7/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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