Konsep SMS Gateway

SMS Gateway providers

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SMS gateway providers facilitate the SMS traffic between businesses and mobile subscribers, being mainly responsible for carrying mission-critical messages, SMS for enterprises, content delivery and entertainment services involving SMS, e.g. TV voting. Considering SMS messaging performance and cost, as well as the level of messaging services, SMS gateway providers can be classified as aggregators or SS7 providers.

The aggregator model is based on multiple agreements with mobile carriers to exchange 2-way SMS traffic into and out of the operator’s SMS platform (Short Message Service Centre – SMS-C), also known as local termination model. Aggregators lack direct access into the SS7 protocol, which is the protocol where the SMS messages are exchanged. SMS messages are delivered in the operator’s SMS-C, but not the subscriber’s handset, the SMS-C takes care of further handling of the message through the SS7 network

Another type of SMS gateway provider is based on SS7 connectivity to route SMS messages, also known as international termination model. The advantage of this model is the ability to route data directly through SS7, which gives the provider total control and visibility of the complete path during the SMS routing. This means SMS messages can be sent directly to and from recipients without having to go through the SMS-Centres of other mobile operators. Therefore, it’s possible to avoid delays and message losses, offering full delivery guarantees of messages and optimised routing. This model is particularly efficient when used in mission-critical messaging and SMS used in corporate communications.

Interconnectivity with other networks

Message Service Centres communicate with the Public Land Mobile Network (PLMN) or PSTN via Interworking and Gateway MSCs.

Subscriber-originated messages are transported from a handset to a Service Centre, and may be destined for mobile users, subscribers on a fixed network, or Value-Added Service Providers (VASPs), also known as application-terminated. Subscriber-terminated messages are transported from the Service Centre to the destination handset, and may originate from mobile users, from fixed network subscribers, or from other sources such as VASPs.

It is also possible, on some carriers, for non-subscribers to send messages to a subscriber's phone using E-Mail. AT&T, T-Mobile^[21], Sprint^[22], Verizon Wireless^[23] offer the ability to do this through their websites mail server. For example an AT&T subscriber whose phone number was 555-555-5555 would receive e-mails to 5555555555@txt.att.net as text messages. Sending a message this way is free but subject to the normal length limit. Primus Canada is one carrier that lacks this feature.

Text enabled fixed-line handsets are required to receive messages in text format. However, messages can be delivered to non-enabled phones using text-to-speech conversion.^[24]

Short messages can also be used to send binary content such as ringtones or logos, as well as Over-the-air programming (OTA) or configuration data. Such uses are a vendor-specific extension of the GSM specification and there are multiple competing standards, although Nokia's Smart Messaging is by far the most common. An alternative way for sending such binary content is EMS messaging which is standardised and not dependent on vendors.

Today, SMS is also used for machine to machine communication. For instance, there is an LED display machine controlled by SMS, and some vehicle tracking companies use SMS for their data transport or telemetry needs. SMS usage for these purposes are slowly being superseded by GPRS services due to their lower overall costs^{[citation needed]}.

AT commands

Many mobile and satellite transceiver units support the sending and receiving of SMS using an extended version of the Hayes command set. The connection between the Terminal Equipment and the transceiver can be realized with a serial cable (i.e. USB), a Bluetooth link, an infrared link, etc. Common AT commands include AT+CMGS (send message), AT+CMSS (send message from storage), AT+CMGL (list messages) and AT+CMGR (read message).^[25]

However, not all modern devices support receiving of messages if the message storage, for instance the device's internal memory, is not accessible using AT commands.

Premium-rated short messages

Short messages may be used to provide premium rate services to subscribers of a telephone network.

Mobile terminated short messages can be used to deliver digital content such as news alerts, financial information, logos and ring tones. The Value-added service provider (VASP) providing the content submits the message to the mobile operator's SMSC(s) using a TCP/IP protocol such as the short message peer-to-peer protocol (SMPP) or the External Machine Interface (EMI). The SMSC delivers the text using the normal Mobile Terminated delivery procedure. The subscribers are charged extra for receiving this premium content, and the amount is typically divided between the mobile network operator and the VASP either through revenue share or a fixed transport fee.

Mobile originated short messages may also be used in a premium-rated manner for services such as televoting. In this case, the VASP providing the service obtains a Short Code from the telephone network operator, and subscribers send texts to that number. The payouts to the carriers vary by carrier and the percentages paid are greatest on the lowest priced premium SMS services. Most information providers should expect to pay about 45% of the cost of the premium SMS up front to the carrier. The submission of the text to the SMSC is identical to a standard MO Short Message submission, but once the text is at the SMSC, the Service Centre identifies the Short Code as a premium service. The SC will then direct the content of the text message to the VASP, typically using an IP protocol such as SMPP or EMI. Subscribers are charged a premium for the sending of such messages, with the revenue typically shared between the network operator and the VASP. Limitations of short codes include the limitation to national borders (short codes have to be activated in each country where the campaign takes place), as well as being expensive to sign up together with mobile operators.

An alternative to inbound SMS is based on Long numbers (international number format, e.g. +44 7624 805000),which can be used in place of short codes for SMS reception in several applications, such as TV voting, product promotions and campaigns. Long numbers are internationally available, as well as enabling businesses to have their own number, rather than short codes which are usually shared across a lot of brands. Additionally, Long numbers are non-premium inbound numbers.

SMS in satellite phone networks

All commercial Satellite phone networks except ACeS and OptusSat fully support SMS^{[citation needed]}. While early Iridium handsets only support incoming SMS later models can also send them. The price per message varies for the different networks and is usually between 25 and 50 cents per message. Unlike some mobile phone networks there is no extra charge for sending international SMS or to send one to a different satellite phone network. SMS can sometimes be sent from areas where the signal is too poor to make a voice call.

Satellite phone networks usually have a web-based or email-based SMS portals where one can send free SMS to phones on that particular network.