Text To Tap Code

#!/bin/bash

#--------------------------------------------------------------------------------------------
# Use:
# echo "Some message" | ./tapcode.sh
# cat somefile.doc | ./tapcode
# Message can only contain a-z or A-Z,
# No numbers (unless spelled out) and
# no punctuation.
# A call sign with a K might be better off
# spelling out the NATO phonetic:
#
# echo "Kilo E eight GGD" |./tapcode.sh
#
# 1,3 2,4 3,1 3,4 - 1,5 - 1,5 2,4 2,2 2,3 4,4 - 2,2 2,2 1,4
#
# I've added the dashes (-) simply as a
# visual marker between words.
#
# To read about Tap Code see Wikipedia:
# https://en.wikipedia.org/wiki/Tap_code
#
#--------------------------------------------------------------------------------------------

tr "[:lower:]" "[:upper:]" |tr '\n' ' '| (
    # while loop
    while IFS= read -r -n1 c
    do
        case "$c" in
            A)  echo -n "1,1 " ;;
            B)  echo -n "1,2 " ;;
            C)  echo -n "1,3 " ;; # Same as K
            D)  echo -n "1,4 " ;;
            E)  echo -n "1,5 " ;;
            F)  echo -n "2,1 " ;;
            G)  echo -n "2,2 " ;;
            H)  echo -n "2,3 " ;;
            I)  echo -n "2,4 " ;;
            J)  echo -n "2,5 " ;;
            K)  echo -n "1,3 " ;; # Same as C
            L)  echo -n "3,1 " ;;
            M)  echo -n "3,2 " ;;
            N)  echo -n "3,3 " ;;
            O)  echo -n "3,4 " ;;
            P)  echo -n "3,5 " ;;
            Q)  echo -n "4,1 " ;;
            R)  echo -n "4,2 " ;;
            S)  echo -n "4,3 " ;;
            T)  echo -n "4,4 " ;;
            U)  echo -n "4,5 " ;;
            V)  echo -n "5,1 " ;;
            W)  echo -n "5,2 " ;;
            X)  echo -n "5,3 " ;;
            Y)  echo -n "5,4 " ;;
            Z)  echo -n "5,5 " ;;
            " ")  echo -n "- " ;;
        esac
    done
)
echo ""