How much does it cost to make SMS device software? Where can I buy a backpack-type car-mounted SMS device?

Customer service of Shenzhen Hongtu Information Technology Co., Ltd.
, No need to know the mobile phone number of potential customers, supports automatic push of text messages to China Mobile and China Unicom mobile phones
, Can be mounted on car mobile text messaging equipment, supports Regional fixed-point push
, one-time purchase and lifetime use, no additional fees, no lifetime recharge, cost of sending text messages
, unlimited sending content, the display number can be optionally set
, and multiple messages can be sent at the same time messages, speed of 10,000 messages/hour, multi-channel, multi-task synchronous work, up to 10,000 messages/day
, metal casing, lowest radiation, small size, simple and user-friendly operation interface
, The time period for sending text messages can be controlled, the coverage range is kilometers
, the time period for sending text messages can be controlled, the time period for sending text messages can be controlled, the time period and frequency of sending text messages can be controlled, and the same customer can only receive one text message