To send / receive SMS messages using SKySMS please organize 2-way SMS. You can buy phone number from SKyPRO company or you can use a GSM modem (or a pool of modems).
Modem pool will mean independence and flexibility. You can use any SIM cards you need, you won't depend on SKyPRO company, you will control everything. Nevertheless you will still have the possibility to use our services, for example for outgoing international messages (as it will be much cheaper than sending them from SIM card).