Merge pull request #20 from OpenDevEd/main

Update 0x40-0x4F.md - added Designer Systems modems

Author: dhalbert

0x40-0x4F.md

@@ -133,14 +133,16 @@
 - [INA260 Precision DC Current/Power Sensor](https://www.adafruit.com/product/4226) (0x40 - 0x4F)
 - [PCF8591 Quad 8-Bit ADC + 8-Bit DAC](https://www.adafruit.com/product/4648) (0x48 - 0x4F)
 - [PCT2075 Temperature Sensor](https://www.adafruit.com/product/4369) (0x28-0x2E, 0x30-0x37, 0x48-0x4F)
+- [Designer Systems pHAT-NBIOT multi-band LTE Cat NB1 module](http://www.designersystems.co.uk/robotics/PHAT-NBIOT_info.htm) (0x4C)
 
 ## 0x4D
 
 - [INA219 High-Side DC Current/Voltage Sensor](https://www.adafruit.com/product/904) (0x40 - 0x4F)
 - [INA260 Precision DC Current/Power Sensor](https://www.adafruit.com/product/4226) (0x40 - 0x4F)
 - [PCF8591 Quad 8-Bit ADC + 8-Bit DAC](https://www.adafruit.com/product/4648) (0x48 - 0x4F)
 - [PCT2075 Temperature Sensor](https://www.adafruit.com/product/4369) (0x28-0x2E, 0x48-0x4F, 0x70-0x77)
-
+- [Designer Systems pHAT-GSM pHAT-GSM quad-band GSM/GPRS module](http://www.designersystems.co.uk/robotics/PHAT-GSM_info.htm) (0x4D)
+  
 ## 0x4E
 
 - [INA219 High-Side DC Current/Voltage Sensor](https://www.adafruit.com/product/904) (0x40 - 0x4F)