| 摘要 |
<p>Two, operationally independent networks (13, 23) are established along a common transmission bus (11, 12) by having the signals for the respective networks propagate in opposite directions, and directionally coupling the station units of the respective networks to the transmission bus so as to receive and transmit signals in one of the two directions. The two networks can operate at different bit rates and wavelengths and, being operationally independent, can be installed and added to at different times.</p> |
