SMS message to Telecom XT SIM (Garbled)


Using an Industrial GSM/GPRS Modem, when sending a message from Vodafone or Telecom Sim we get the following results:

- Sending to Vodafone NZ       WORKS

- Sending to 2degrees            WORKS

- Sending to TELECOM XT        Message arrives but text is garbage
  The words “Test message” arrives as:  TJM#ì¤Ä2sfé;V


Any ideas why Telecom XT network is giving garbled SMS message ?