What is the SMSC number or Message Center number :


To communicate with the other nodes in the SS7 network, each node requires an address known as a global title (GT).  For example, the nodes can be HLR, GGSN, SMSC etc. Smsc or message service centre number is the Global title/Address of SMSC. It is also known as a message centre number, located in HPLMN of a mobile network operator.

A mobile operator uses SMSC for providing SMS services to subscribers. The number is an E.164 type of number. Similar to any other mobile global title,  it has digits along with other information. Sim card stores the message service centre number.

SMSC GT in SS7 Network
SMSC GT in SS7 Network

What are the operations of the GSM protocol (MAP 09.02) for messaging over a telecom network?

There are two messages. MO-ForwardSM is used to send text from a mobile phone, while MT-ForwardSM is used to send a text to a mobile phone.

For a mobile-originated SMS, the SCCP called party address is the SMSC number in the MO-ForwardSM message of the GMS map protocol, and for a mobile-terminated SMS, the SCCP calling party address is the SMSC number in the MT-ForwardSM map operation.

How phone uses an SMSC number for outgoing text (MO-SMS)?

The SS7 protocol is used to send SMS messages. When a user sends an SMS, it is routed through the roaming network’s VLR. From SMS, VLR obtains the SMSC number or GT. VLR sends MO-SMS to the service centre based on GT.

An SMS may be in multiple parts, SMSC does the assembly of message segments.  Each segment has an SMSC number called party. The SMS  from VLR to SMSC uses the SS7 protocol.

How does SMSC use the number for mobile terminated text(MT SMS)?

While sending MT-SMS, SMSC set in calling party its own SMSC number or GT. So that the responses can be routed back, from the destination network.  Two GSM MAP operations (SRI-SM and Forward-SM) over ss7/ Sigtran are used by SMSC for MT-SMS.

SMSC tutorials -Protocols Explained.

How to change the SMSC number on phone?

Once a sim card is inserted into the mobile device, the service centre address is automatically set or updated by the mobile carrier over the air. But still, there are circumstances when outgoing SMS is not working.

This may be because the SMSC number stored in the phone is not correct or mobile subscriber is not allowed for messaging service.

In both cases, the mobile subscriber needs to call customer care.  If SMS is not working because of, no subscription for messaging service on HLR.  The customer care executive can update the subscription profile on HLR for SMS service.

If the SMSC address is not correct then based on the model and brand of the phone device, the customer care executive can guide to change the SMSC number with the correct value.

How to update the SMSC number in Android?

  • 1. Go to the home screen.
  • 2. Click on the messaging app.
  • 3. On top, side click, ad go to settings.
  • 4. More settings.
  • 5. Text Messaging.
  • 6. Message Centre.