Silent SMS technology

What is silent SMS

Silent SMS messages are specially encoded text messages that can do through the network and can trigger status and delivery reports, but are not displayed on the recipient's mobile phones.

Common requirements for silent SMS messages

The common requirement for silent SMS users is to send a special MO SMS with attributes configured to avoid detection on the recipient handset. The following attributes should be honoured on both Android and Apple iPhone mobile phones:

• The SMS is not displayed on the screen of the mobile device
• No notification sound is played on the mobile device
• The SMS is not stored on the mobile device
• The SMS is not stored on the SIM card
• No notification icon is displayed on the lock screen
• No notification popup is displayed if the device is unlocked
• No notification icon is displayed on the top bar
• Not forwarded to Apple watch / smartwatches
• The mobile device disposes of the SMS immediately
• An SMS delivery report is returned to the SMS gateway

Ozeki SMS Gateway can send silent SMS messages with the above attributes.

How can silent SMS be delivered to the mobile network

Silent SMS messages can be delivered by the Ozeki SMS gateway to the mobile network through various connections. Silent text messages can be sent to the mobile network through wireless links or through Internet-based SMS connections or through direct SMS connections to the Short Messages Service Centre (SMSC) of a mobile network.

Wireless (so called mobile) connections send the silent SMS messages the same way as standard SMS messages are sent. In this case, the silent SMS is sent through a standard mobile terminal equipment (standard mobile phones with a SIM card). These messages are sent as MO (mobile originated) SMS messages. For example, silent SMS messages can be sent using an Android Mobile phone if it is connected to Ozeki SMS Gateway over a Wifi link.

Silent SMS messages can also be sent through GSM modems or GSM modem pools. A GSM modem is a standard mobile phone without a screen. A GSM modem pool contains multiple GSM modems. GSM modems and GSM modem pools are connected to a Windows PC where Ozeki SMS Gateway is installed. The modem (or modem pool) is connected to the PC using a USB data cable. Every GSM modem needs a SIM card. A modem pool needs multiple SIM cards: one for each modem in the pool. Any SIM card provided by any mobile network operator can be used to send silent SMS messages, as long as it has sufficient money (balance) to send SMS messages.

It is also possible to use Ozeki's hardware SMS gateway to send silent SMS. Ozeki's hardware SMS gateway is a professional, industrial PC with a built-in SMS modem. It is fast and efficient and can deliver silent SMS messages over 4G LTE and 5G connections to the mobile network. These connections are very fast by default, so silent SMS messages delivered through Ozeki's hardware SMS gateways reach the network quickly.

If a very large number of silent SMS messages need to be sent IP sms connections using SMPP, CIMD2 or UCP can also be used to deliver the silent SMS messages. The protocol implementations of these protocols in the Ozeki SMS Gateway support silent SMS encoding.

How do users send silent SMS messages

Silent SMS messages are often sent using the Graphical user interface of Ozeki SMS Gateway. The user selects the silent SMS type from the available SMS message types, then enters the mobile phone of the recipient and clicks on send. Ozeki SMS Gateway sends the silent SMS to the mobile network, and waits for the SMS submit status report and SMS delivery report returned by the network.

After the silent SMS has been delivered the Ozeki SMS gateway displays the SMS submit reference and the delivery report information including the delivery timestamp of the user on the Graphical user interface.

The user of Ozeki SMS Gateway will know from this information if his silent SMS messages were delivered successfully and if the recipient's mobile phone is turned on and is available on the mobile network.

The recipient of the silent SMS message does not notice anything about the SMS reaching his mobile phone. As soon as the SMS reaches the mobile phone, it is dropped and deleted by the device.

Silent SMS GUI of Ozeki SMS Gateway

The silent SMS sending GUI of Ozeki Gateway is used by human operators, who put it in the phone numbers to "ping". The silent SMS messages are entered on the graphical user interface. The human operators can schedule the message sending frequency and can set the start and end date/time of the ping operation. The configuration is customizable for each phone number.

A report of the ping operation is available on a per phone number basis, that clearly shows when silent SMS messages were sent, and which of these SMS messages were confirmed by a delivery report.

The user interface of Ozeki SMS Gateway can only be accessed by operators in the LAN through a web browser.