手機(jī)短信的發(fā)送主要借助于VB的Mscomm控件實(shí)現(xiàn),關(guān)于Mscomm控件,前面的技術(shù)介紹部分有詳細(xì)介紹。短信的發(fā)送是由AT+CMGS指令完成的,采用PDU模式發(fā)送,函數(shù)代碼如下:
Const prex = "0891"
Const midx = "11000D91"
Const sufx = "000800"
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(1)
mobcomm.Output = "AT+CMGF=0" + vbCr
mobcomm.Output = "AT+CMGS=" & Str(15 + length) + vbCr
mobcomm.Output = pdu & Chr$(26)
sleep(1)
Sendsms = True
End Function
因?yàn)槭謾C(jī)同一時(shí)間只能處理一件事情,因此這個(gè)函數(shù)只負(fù)責(zé)發(fā)送短信,關(guān)于短信發(fā)送成功與否以及閱讀短信的部分集中在一起處理。判斷手機(jī)短信發(fā)送成功與否主要由AT+CMGS命令執(zhí)行以后的返回碼來(lái)決定(可參見(jiàn)前文的AT指令介紹部分)。
為了防止手機(jī)因過(guò)于繁忙而出錯(cuò),這里采取了一定的方法讓手機(jī)有充分的時(shí)間處理發(fā)送和接收及刪除等操作。Sleep()函數(shù)正是為此而設(shè)計(jì)的,在發(fā)送及刪除操作后都會(huì)讓程序暫停一秒,這樣就不至于使得手機(jī)過(guò)于繁忙。
Unicode碼解碼函數(shù)
相比于手機(jī)短信的發(fā)送而言,手機(jī)短信的接收主要的工作正好與之相反。手機(jī)短信的發(fā)送需要將待發(fā)送的短信內(nèi)容轉(zhuǎn)換為Unicode碼,而短信的接收則需要將接收到的Unicode碼轉(zhuǎn)換成中文字符。下面的函數(shù)將實(shí)現(xiàn)解碼功能。同手機(jī)短信發(fā)送的編碼函數(shù)一樣,這里也應(yīng)用了一個(gè)VB內(nèi)置的函數(shù)AscW()函數(shù)來(lái)將Unicode碼轉(zhuǎn)換為中文:
Public Function ascg(smsg As String) As String
Dim si, sb As Integer
Dim stmp As Integer
Dim stemp As String
sb = Len(smsg)
ascg = ""
For si = 1 To sb
stmp = AscW(Mid(smsg, si, 1))
If Abs(stmp) < 127 Then
stemp = "00" & Hex(stmp)
Else
stemp = Hex(stmp)
End If
ascg = ascg & stemp
Next si
ascg = Trim(ascg)
End Function
2 手機(jī)短信接收函數(shù)
相對(duì)于短信的發(fā)送函數(shù)而言,短信的接收相當(dāng)簡(jiǎn)單,只需要以下的三行代碼就完成了。但是它使用的技術(shù)卻決不比短信的發(fā)送少,這里主要用到了Mscomm控件的Output屬性和AT+CMGR指令。
Public Sub readsms(rnum As String)
mobcomm.Output = "AT+CMGF=1" + vbCr
mobcomm.Output = "AT+CMGR=" & rnum + vbCr
End Sub