首(shou)先(xian)得先(xian)說明一(yi)下中(zhong)(zhong)繼(ji)(ji)(ji)線(xian)(xian)(xian)和電(dian)話(hua)線(xian)(xian)(xian)的概念普通(tong)固話(hua)（含個人(ren)手機(ji)），為模擬數字線(xian)(xian)(xian)路，一(yi)般只能(neng)承載一(yi)路呼(hu)(hu)入或(huo)者(zhe)呼(hu)(hu)出(chu)功(gong)(gong)能(neng)同(tong)時兩個人(ren)撥打同(tong)一(yi)號(hao)碼，就(jiu)(jiu)會(hui)提示(shi)用戶(hu)(hu)(hu)忙音。而中(zhong)(zhong)繼(ji)(ji)(ji)線(xian)(xian)(xian)呢，是數字電(dian)話(hua)線(xian)(xian)(xian)，也(ye)稱為30B+D線(xian)(xian)(xian)路，可(ke)以(yi)同(tong)時最多(duo)承載15線(xian)(xian)(xian)呼(hu)(hu)出(chu)+15線(xian)(xian)(xian)呼(hu)(hu)入。由此可(ke)見(jian)，一(yi)般400綁定坐(zuo)席均為一(yi)般的普通(tong)固話(hua)，中(zhong)(zhong)繼(ji)(ji)(ji)線(xian)(xian)(xian)路一(yi)般為大(da)型客(ke)(ke)(ke)戶(hu)(hu)(hu)專用。400電(dian)話(hua)的中(zhong)(zhong)繼(ji)(ji)(ji)功(gong)(gong)能(neng)，其實就(jiu)(jiu)是一(yi)個中(zhong)(zhong)繼(ji)(ji)(ji)線(xian)(xian)(xian)對接功(gong)(gong)能(neng)。也(ye)就(jiu)(jiu)是說，本身需(xu)要(yao)(yao)客(ke)(ke)(ke)戶(hu)(hu)(hu)自己向(xiang)運營商(shang)申請中(zhong)(zhong)繼(ji)(ji)(ji)號(hao)碼及中(zhong)(zhong)繼(ji)(ji)(ji)線(xian)(xian)(xian)路。因為一(yi)般客(ke)(ke)(ke)戶(hu)(hu)(hu)綁定的號(hao)碼均為普通(tong)固話(hua)和手機(ji)，400運營商(shang)會(hui)默(mo)認客(ke)(ke)(ke)戶(hu)(hu)(hu)都是綁定普通(tong)固話(hua)和手機(ji)。當客(ke)(ke)(ke)戶(hu)(hu)(hu)的400電(dian)話(hua)需(xu)要(yao)(yao)綁定中(zhong)(zhong)繼(ji)(ji)(ji)線(xian)(xian)(xian)時，需(xu)要(yao)(yao)單獨申請開(kai)中(zhong)(zhong)繼(ji)(ji)(ji)功(gong)(gong)能(neng)，以(yi)便在對接的時候能(neng)實現中(zhong)(zhong)繼(ji)(ji)(ji)功(gong)(gong)能(neng)，如果沒開(kai)中(zhong)(zhong)繼(ji)(ji)(ji)功(gong)(gong)能(neng)會(hui)出(chu)現，將客(ke)(ke)(ke)戶(hu)(hu)(hu)中(zhong)(zhong)繼(ji)(ji)(ji)號(hao)碼默(mo)認判定為普通(tong)號(hao)碼，導(dao)致高話(hua)務的客(ke)(ke)(ke)戶(hu)(hu)(hu)，大(da)量(liang)話(hua)務進不來。所(suo)以(yi)，400電(dian)話(hua)如果綁定中(zhong)(zhong)繼(ji)(ji)(ji)線(xian)(xian)(xian)，一(yi)定需(xu)要(yao)(yao)聯系(xi)400電(dian)話(hua)提供商(shang)開(kai)通(tong)中(zhong)(zhong)繼(ji)(ji)(ji)功(gong)(gong)能(neng)！