looks like you just need a midi cable and the midi to 1/8" TRS adaptor that comes with the SQ-1. this will sync the DT to the SQ-1. if you want to do the opposite, you need to use a computer and the USB port.
Synchronizing an external device to the SQ-1
You can use MIDI OUT (including USB-MIDI) or SYNC OUT to synchronize a MIDI device, volca, or electribe to the SQ-1. SYNC OUT lets you synchronize the tempo of a monotribe, volca, or electribe. By connecting an external MIDI device to MIDI OUT, you can also control the sequencer’s start/stop as well as tempo synchronization.
source: https://www.korg.com/us/products/dj/sq_1/faq_tips.php