User manual

GSM modem protocol for pCO
2
Carel code +030220330 Rel. 2.0 del 30/10/02
21
2.2.2 Disabling the PIN code
GSM modems, like GSM phones, need a SIM card to work. This can be set with a code (PIN) to protect the usage of the card,
yet that also prevents connection between the modem and the pCO
2
.
During the modem initialization procedure, the pCO
2
checks if the PIN code has been disabled. If not, it signals via a system
variable that the PIN is enabled and that consequently it has to be disabled.
Generally, the enabling of the PIN can be checked visually, if the modem features a status LED. If, after turning on the
modem, this LED stays on red, this means that the modem requires the PIN to be entered and that therefore you have to
disable it. This can be done simply by turning on the modem before connecting it to the pCO².
As for disabling the PIN code, see the modem manual. However, the operation can be carried out by inserting the modem SIM
in any cellular phone and using the main menu on the phone.
2.2.3 Entering the Service Centre number
If you want to send SMS messages using the GSM modem, you have to enter the Service Centre number for the telephone
operator set in the SIM card. To enter the Service Centre number, refer to the modem manual. However, the operation can be
carried out by inserting the modem SIM in any cellular phone and using the main menu.
2.2.4 Deleting all messages before utilization
Before connecting the modem to the pCO², particularly if the SIM card is also used in cellular telephones, it is preferable to
delete all the messages received so as to clear the SMS memory.
If you cannot do this by inserting the SIM in a cellular phone and using, for example, the “Delete All” command in the
message menu, you can use HyperTerminal for Windows
TM
(see
Disabling the modem flow control
) by sending the modem the
following type of messages:
AT+CMGD=N
↵
N has a variable value from 1 to 10, indicating the memory position occupied by the message to be erased.
For each erased message the modem will answer “OK”.
After the first message has been erased, the HyperTerminal window will appear as follows :
WARNING
. The modem deletes the messages using the AT+CMGD command, independently of whether or not there is a
message to be deleted in the specified position.