Terms and definitions in messaging

Multichannel messaging service is based on a variety of telecommunication and Internet technologies. In the description of services, we often use abbreviations that may not always be known to you. Here we have compiled a glossary of terms and definitions used in the industry.

DEF Code

Each subscriber has a mobile telephone number, and in many countries (not all), mobile number ranges are different from fixed line (land line) number ranges. In countries where the mobile number range is separate from the range for fixed line numbers, the country’s telecommunications regulator (for example the regulatory body in the UK is Ofcom) may issue numbers to Mobile Operators in blocks. These blocks can be used to identify the mobile operator to which the number belongs. In countries where Mobile Number Portability (MNP) is not allowed, these DEFs can be used to determine the Home Operator, as the Home Operator equals the DEF Code. In countries when MNP is allowed, then another source of porting information is required to determine the Home Operator, and the DEF Code is relatively meaningless and only indicates to which operator the number was originally allocated. In the world of SMS the DEF Code can be important for routing, as some routes only support certain DEF/home operator combinations. Be careful of aggregators who only support DEF routing, as this implies they do not support MNP routing, which is required in 68 countries in the world to deliver a message effectively.