The idea was born from the knowledge that everyone of us has in the drawer at least one old GSM phone, that, for varied reasons, we do not use! The following application is realized using a PIC microcontroller connected to Ericsson T18 phones, testing the compatibility also with A1018 and T28. But it is not commercialized for reasons of difficult availability of the connectors, instead it can be a lot interesting for hobby use.
Moreover at the end of the post you can view the links for having other combinations of Microcontroller and cell phones.

The target is remote activated (boiler, control relais..etc.) or receiving SMS in alarm case (gas or burglar alarm) to give again a life to our old cellular

GSM2 [ bidirectional GSM Remote Control - remote activator - receiver of SMS alarms - ]

This is the picture of the ended project, the missed components are optional (Quartz Y1 and J1 connector...).The J2 connector is used in order to connect GSM2 to phone, therefore you will have to use a cable with connectors evidently adaptable to the used telephone.

This is ALL the documentation for the realization of GSM2 design.

Brochure gsm2_istr.pdf

Manual gsm2_rev3.pdf

Schematic, PartList, PCB and Firmware YOU CAN DOWNLOAD HERE--->> DOWNLOAD

Useful Resources to use various phones and also various microcontrollers but with the same target, to realize GSM remote control.

Remote Control and monitoring with Atmel TINY12L and a phone Ericsson (tested with the Ericsson T10s, T28 and R320 only)
Review on issue 142 of the magazine Circuit Cellar

link ---> Tiny Planet

Remote Control with 2 relais controlled by a serial com RS232 and a module Wavecom You can connect it to the PC and command the module by your keyboard on the PC with OpenAT Command.
Review on issue 317 (january 2003) of the magazine Elektor Electronics

link---> SMS-Controlled Mains Sockets

Remote control and monitoring by SMS with the use of microcontroller Atmel AT89S8252 and a phone
Siemens '35' series. Compatible with command AT
Review on issue 306 (january 2002) of the magazine Elektor Electronics

link ---> Remote Process Control using a Mobile Phone

SMS remote control with a Motorola microcontroller (Freescale) 68HC705C8 and a NOKIA 5110 phone. You can control by SMS up to 7 power relais.

GSM remote control with a PIC microcontroller and a SIEMENS A65 phone. You can control 2 output relais and to have 2 input for alarm signals, moreover there are also present 3 I2C lines for future expansion.

link ---> Remote control GSM Siemens A65