The best replacement for ttl is cmos.

The best alternatives to ttl are rated as following:
★★★★★  cmos
★★★  ettl
★★★  rs232
★★  ttl bl
★★  manual flash
★  ittl
★  ecl
★  ettl flash
★  i-ttl
★  cmos levels
★  no ttl
★  lvds
★  non ttl
★  ttl-bl
  lvttl
  cmos logic
  htl
  analog modulation
  auto flash
  not to ttl
  schmitt trigger
  ettl canon
  htl encoder
  flip up loupes
  e ttl
  ttl
  adi
  e-ttl

Your alternative for ttl is not listed? Suggest!
Speaking about ttl, one probably shouldn't forget about off camera flash.

Other search terms related to ttl and their ratings are:
★★★★★ off camera flash
★★★★ pocket wizard
★★ cmos
★ nslookup
★ pocket wizards
★ flash
You have in mind a companion for ttl and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of ttl in all years. Click on graph for more.
ttl
cmos
ettl