A simple way of connecting two repeaters is to link them directly as you would with a reflector. This allows users to respond via the usual Gateway CQ configuration without needing to know the repeater or enter the callsign of the remote station.
To do this, the UR field of the sending repeater needs to be set to the callsign of the receiving repeater with a L in the 8th positon. For example, if you wanted to link to the W8TST B node, you would enter W8TST BL in the UR field of your radio.
If the repeater callsign were longer like WT8EST, you would need to omit the space, so you'd enter WT8ESTL in the UR field of your radio.
Once configured, you'd briefly send a transmission and if the link is successful you should hear a message confirming the link.
After linking successfully, set your radio to Gateway CQ mode. Transmissions will be sent from your local gateway to the remote gateway repeater and all stations listeing to either repeater will hear the response, but only stations using Gateway CQ or callsign routing will be able to respond.
Be sure to send the Unlink command " U" (7 spaces followed by a U in the 8th position) to unlink the repeaters when you are done. If successful, you should hear a message confirming the unlink. Most repeaters will automatically unlink after a period of inactivity, but it's good practice to unlink when you are done.
When attempting to link, sometimes you may hear a message indicating that the link is already in use. This means that someone else is already using the link. If you are sure that you are not interrupting a conversation, you can try again in a few minutes.
If a user can't link to a repeater, they could also try original routing but it's important to inform listeners of the sending repeater and node so they can reply, otherwise they'd need to use callsign routing.