Question

What encoding standards does Vonage support in SMS?

Applies To

• SMS
• Encoding

Answer

Vonage supports both GSM-7 and UCS-2 character encoding types.

• GSM-7
  • Is the default encoding standard, which includes the most common characters. It uses 7 bits to send a single character/symbol on GSM networks. As single SMS messages are transmitted as 140 8bit octets simultaneously, GSM-7 encoded SMS messages can carry up to 160 characters (140 * 8bit / 7bit per character).
  • Some characters, such as | ^ € { } [ ] ~ \ will be encoded using two characters (E.g. Hello =  5*7 = 35bits, while Hell€ = 4*7 + 2*7 = 42 bits) as it requires an escape code. You can find out what characters are included in the GSM-7 set here.
  • When you set the type parameter to text to the SMS API, characters within the message are encoded using GSM-7.
• UCS-2
  • Languages such as Arabic, Chinese, Korean, Japanese, or Cyrillic alphabet require Unicode characters beyond the GSM standard and extended ranges. These characters require 16-bit UCS-2 encoding. Refer to encoding details here.

Additional Information

Additionally, for long messages more significant than 160 GSM-7 characters or 70 Unicode characters, Vonage will split the message into multiple segments. You can find details in our developer guide here. Though Vonage supports UCS2, there can be country restrictions which restrict the use of Unicode characters. Please take a look at the Outbound-SMS-Features-Overview to know if Unicode is supported.