Ring Buffer lib: https://github.com/rlogiacco/CircularBuffer

To change the Operator Mode:

• hang up, pick up, hang up, pick up, dial digit for operator mode to toggle
• modes:
  • 1: Serial (print what number was dialed)
  • 2: NeoPixel
  • 3: SMS Message Content
  • 4: SMS Recipient phone number
  • 5: SMS message manager (send message)
  • 6: Operator mode manager (displays the enabled/disables status for each mode)

Recipient phone number:

• enter 555 to clear the phone number SMS Message Content:
• enter text in 2 key sequences.
  • The first number is the character group - what key on the phone pad the letter is assigned to. The 2nd key is the position within that group.
  • Example: the 4 key has letters GHI. So to dial 'h', you would neter 42. 4 as the character group key, then 2 because H is the 2nd letter in GHI
  • Group 7 is PQRS, group 9 is WXYZ, all other groups are 3 letters
  • All lowercase. Potential enhancement.
• the 0 group is for deleting text
  • 0 1 deletes the last character
  • 0 0 deletes the entire message
• the 1 group is for non-alpha characters (punctuation) SMS Manager:
• dial 7 to connect to wifi
• dial 4 to send message to recipient
• uses twilio to send messages