diff --git a/V1.5/STM32F103_App1/HardWare/CAR/air780e.c b/V1.5/STM32F103_App1/HardWare/CAR/air780e.c
index 3b5fabd..b2a7494 100644
--- a/V1.5/STM32F103_App1/HardWare/CAR/air780e.c
+++ b/V1.5/STM32F103_App1/HardWare/CAR/air780e.c
@@ -312,7 +312,8 @@ static int cat_connect_network(void) {
                 p += 7;
                 while (*p == ' ') p++;
                 int n = 0;
-                while (p[n] >= '0' && p[n] <= '9' && n < 19) n++;   /* 只取 19 位卡号本体，末位校验字符(可能印成字母)不上传 */
+                while (n < 20 && ((p[n] >= '0' && p[n] <= '9') ||
+                       (p[n] >= 'A' && p[n] <= 'Z') || (p[n] >= 'a' && p[n] <= 'z'))) n++;   /* 数字+大小写字母都保留，最多 20 位 */
                 memcpy(s_iccid, p, n);
                 s_iccid[n] = 0;
             }