Most probably, it seams that SER is not able to "see" your modem. You don't need any driver or any supplementary application in order to use your modem (phone) via serial cable in Linux. To be sure, please test your modem connectivity using "minicom" - set device = /dev/ttyS0 , ECHO = on, etc. See if your modem responds to the "AT" command - it should reply with "OK". Regarding your second question, let me make you a short explanation about how the SMS module works: - from SIP->SMS : send with a SIP UAC a SIP MESSAGE to your SER. Using the script function"sms_send_msg", SER will send an SMS having as text the body from the SIP message. The SMS destination (that is a mobile phone number) has to be specified into user part of the Request URI of the SIP message (for more details see the README). - from SMS->SIP : from a mobile phone send a SMS to the GSM device attached to SER - SMS the gateway - (in your case, the MOTOROLA phone). Regarding how the SMS should look like, see the README. Once the SMS received by SER (through the SMS GW), the message will be forwarded as a SIP message to a SIP UAC. Please don't hesitate to contact me for any further problems! Best regards, Bogdan Joe_chen wrote: