请选出不是WAMS主站与PMU子站通信需要建立的通道（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='29465' and id < 2399171 and id<>'2399171' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='29465' and id > 2399171 and id<>'2399171' order by id asc limit 5