This paper deals with the stability analysis of two haptically-coupled devices. It describes how to model this kind of systems and shows how to obtain stable linking impedances. The approach is applied to an experimental setup that consists of a bimanual driving system in which both devices are haptically coupled. Four different cases depending on system dynamics are considered: 1) identical rigid devices, 2) different rigid devices, 3) different devices with vibration modes, and 4) mechanically-linked devices with vibration modes. The theoretical analysis is validated with experiments carried out on a driving simulation platform. The influence of the human operator is also experimentally discussed. Results can be extended to other applications where two haptic devices are used to hold virtual objects.