The modular sensor and zone bus ports on the front of the ZEC510 are RJ12, six-position, modular jacks. The modular sensor bus ports provide a connection for the VAV Balancing Tool. The zone bus port is not used in ZEC510 installations. The following figure shows the pin number assignments on the modular port.
Figure 1. Pin number assignments
| 1 | Power 15 VDC |
| 2 | Bus and power common |
| 3 | Power 15 VDC |
| 4 | Bus and power common |
| 5 | Sensor or zone bus - |
| 6 | Sensor or zone bus + |