怎么提高短信发送成功率,小弟我的代码发送4次丢一次

如何提高短信发送成功率,我的代码发送4次丢一次
mobcomm.RThreshold   =   1
mobcomm.CommPort   =   1
mobcomm.InputLen   =   0  
mobcomm.PortOpen   =   True

Private   Sub   Command1_Click()
Sendsms   "13800739500 ",   phonecode.Text,   msg.Text  
End   Sub

Public   Function   Sendsms(csca   As   String,   num   As   String,   msg   As   String)   As   Boolean
          Dim   pdu,   psmsc,   pnum,   pmsg   As   String
          Dim   leng   As   String
          Dim   length   As   Integer

          length   =   Len(msg)
          length   =   2   *   length
          leng   =   Hex(length)
          If   length   <   16   Then   leng   =   "0 "   &   leng
          psmsc   =   Trim(telc(csca))
          pnum   =   Trim(telc(num))
          pmsg   =   Trim(ascg(msg))
          pdu   =   prex   &   psmsc   &   midx   &   pnum   &   sufx   &   leng   &   pmsg

        Sleep   (100)
          mobcomm.Output   =   "AT+CMGF=0 "   +   vbCr
          Sleep   (200)
          mobcomm.Output   =   "AT+CMGS= "   &   Str(15   +   length)   +   vbCr
          Sleep   (200)
        mobcomm.Output   =   pdu   &   Chr$(26)
        'Sleep   (500)
          Sendsms   =   True
          MsgBox   "ok "
        End   Function

[解决办法]
移动问题。。。为了防止乱发垃圾短信。

建议每次发送消息间隔时间拉大一点。具体多少，一次次尝试，得到经验值。