Does TM4B support delivery to ISDN's (i.e. normal landlines)?
Whilst we do have the physical capability of delivering MT SMS to landlines (where such facilities exist), we are yet to make this available to all our customers because a huge effort and responsibility is involved.
To explain, when an SMS is submitted to an SMSC, values need to be provided which indicate that the recipient number is an ISDN (i.e. land-line) as opposed to an MSISDN (i.e. mobile handset). Knowing the complete numbering plan of every country in the world and then validating recipient numbers against all of these numbering plans to distinguish MSISDN's from ISDN's is a huge effort that would take a serious toll on the speed of message submission.
Furthermore, as countries' numbering plans change very frequently, the added responsibility of staying completely up-to-date on every country's numbering plans to ensure that our customers' messages are submitted accurately must also be included.
However, as the ability to delivery MT SMS to landlines is possible, potentially 'large' customers who wish to terminate MT SMS in a single country may contact us to investigate the possibility of us providing SMS-to-ISDN for that country.