发明名称 |
PACKET DATA COMMUNICATION SYSTEM |
摘要 |
A packet data transmission system is used to link a number of remote han d- held data-gathering units such as bar code readers to a central computer whi ch maintains a database management system. Data packets are sent from the remot e units by an RF link to intermediate base stations, then sent by the base stations to the central computer by a serial link. Direct sequence spread spectrum modulation is used for the RF link. The remote hand-held units initiate an exchange usi ng RF transmission to and from the base stations, receiving only during a rigid ti me window following a transmission from the remote unit. The base stations cann ot initiate communication to the remote units, but instead send data to the remote units only as part of the exchange.
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申请公布号 |
CA2072345(C) |
申请公布日期 |
2004.05.04 |
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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