A paddle cable is probably already attached to your iambic paddle. If the plug is a 1/4" style you will need a 1/4" to 1/8" adapter in order to plug it into the K45.
Audio cabling is dependent on the radio receiver or transceiver you are using. The best solution is to use your radio's audio line output. Depending on the radio, this could be on on a separate 1/8" or RCA jack. Usually it is grouped with other signals on an AUX connector. Refer to your radio manual to determine what mating connector is required and what the pinout is. If you happen to have a SignalLink Interface (or equivalent) connected to the radio's AUX connecter, it may have an 1/8" AUX output which will work perfectly as a source for K45 audio.
The radio's external speaker could be used as an audio source but you will find that when you plug the K45 audio cable into your transceiver's external speaker output the transceiver's internal speaker will be disabled. This means you wil need a splitter Y cable:
The CW keying input jack on most transceivers is either a 1/4" or 1/8" stereo phone type which normally accepts an iambic paddle input. The K45 uses an 1/8" stereo output jack so you may be able to use a 1/8" to 1/8" inch cable. Otherwise you'll need a 1/4" to 1/8" plug adapter. You will need to disable your radio's internal keyer and run it in straight key mode. In almost all cases, the PTT output will not be used, we recommended using a stereo connector and disable the K45's PTT output. The PTT ring connection is really only used to key an amplifier or activate an antenna changeover relay.
We offer an accessory cable kit that covers most setups which consists of two cables (1/8" stereo to 1/8" stereo) and one 1/4" to 1/8" adapter. One of the cable would be used for audio and the other for transceiver keying. The adapter, if needed, could be used on either the paddle cable or transceiver cable.
The USB host cable is a USB A to USB Mini B type. We include one with every K45.