| SPECIAL VERSION |
| Code | Description |
| RTL 520/AG | Wall-mounted local unit with 0...10 Volt DC relay output, enclosure silver finish |
| RTL 520/AL | Wall-mounted local unit with 0...10 Volt DC relay output, enclosure aluminium finish |
| RTL 520/B | Wall-mounted local unit with 0...10 Volt DC relay output, enclosure black finish |
| RTL 520/GY | Wall-mounted local unit with 0...10 Volt DC relay output, enclosure grey finish |
| ACCESSORIES |
| Code | Description |
| ASA 2418 | Cable for powering RTL 1.. and RTL 5.. directly with 24 V AC |