Which statement about mid cable specifications is correct?

Which statement about mid cable specifications is correct?

• A. It has a maximum backbone length of 250 meters and a maximum drop length of 6 meters
• B. It has a maximum backbone length of 250 meters but no drop length
• C. It has a maximum drop length of 6 meters but no backbone length
• D. It has neither backbone length nor drop length

Answer: (A)

In NMEA 2000, mid cables belong to the trunk-and-branch layout, where the trunk (backbone) runs through the system and devices connect to it via short drops. The specifications for a mid cable set limits on both parts: how long the backbone can be and how long a drop from that backbone to a device can be. The backbone is limited to a long run to keep the CAN signaling within its electrical and timing requirements, while each device drop must be kept short to preserve signal integrity and proper termination. Therefore, the correct statement is that the mid cable allows a backbone length up to 250 meters and a drop length up to 6 meters. This combination ensures reliable communication across the network. The other options would ignore one of these necessary limits, which isn’t consistent with how mid cables are defined.

In NMEA 2000, mid cables belong to the trunk-and-branch layout, where the trunk (backbone) runs through the system and devices connect to it via short drops. The specifications for a mid cable set limits on both parts: how long the backbone can be and how long a drop from that backbone to a device can be. The backbone is limited to a long run to keep the CAN signaling within its electrical and timing requirements, while each device drop must be kept short to preserve signal integrity and proper termination. Therefore, the correct statement is that the mid cable allows a backbone length up to 250 meters and a drop length up to 6 meters. This combination ensures reliable communication across the network. The other options would ignore one of these necessary limits, which isn’t consistent with how mid cables are defined.