connectionInfo only requires a single object.attr.
listConnections also works, but this is a bit more simple:
// Is the object.attr a source of a connection?
connectoinInfo -isSource object.tx;
// Is the object.attr the destination of a connection?
connectionInfo -isDestination object.tx;
// List an object.attr's source connection, meaning, list the input connection.
// This will return a single object.attr.
connectionInfo -sourceFromDestination object.tx
// List an object.attr's destination connection, meaning, list the all output connections:
// This could return multiple object.attrs.
connectionInfo -destinationFromSource object.tx;