Adafruit I2C Multiplexer TCA9548A - 8-Channel Mux 1674 You could use this cable

You could use this cable for most GSM modules available

1 mm Antenna Onboard PCB antenna + IPEX connector Frequently Asked Questions

Several electrical stores and online sellers like as Circuit Rocks

Patch Antenna Size: 15mm x 15mm x 4mm

which are used to connect the board to other devices or sensors using conductive thread

Adafruit I2C Multiplexer TCA9548A - 8-Channel Mux 1674 You could use this cableIf you want to use the same component, sensor, or module with the same I2C address that you cannot modify, you may do so using another I2C library different from the wire library pre installed in the Arduino IDE. The problem using this library is that you also need to revise the libraries to be used that is dependent on the wire library. Another solution is to use a hardware I2C multiplexer, that could give you more I2C busses. This module uses