Chasing OLD SeaTalk cables...

[snfriends]

Slowly, I am replacing older ST60 instruments, with new technology from Raymarine throughout the yacht. Keeping the speed, depth and Wind for the time, but the Autopilot, GPS and MFD are updated with STNG cables. So that I do not cripple myself, how can I test a SeaTalk cable to determine if it has any power, and/or transmission data live on the line? (Trying to effectively discard the old system wiring for the new STNG cableing...) Thanks.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Neumann,

Please click here to view a FAQ addressing how to interface devices having a SeaTalk communications interface to a SeaTalkng backbone. With respect to SeaTalk communications cables, the following three leads may be found within each:
- red: +12VDC
- yellow: Data ... when data is present on the SeaTalk bus, the needle of an analog voltmeter will pulse between +9 to +11VDC
- shield: -12VDC / ground

[snfriends]

CHUCK, thanks for the clarification. Some of the SeaTalk cables in this 20 year old yacht, have 6 wires, therefore, the balance of the wiring should be technically "dead" with no voltage being shown (Red to BLue for an example... 0-volts DC).

Appreciate your timely response.

Steve Neumann

[Chuck - Raymarine - Moderator]

Steve,

SeaTalk is now and has always been a three conductor communications protocol having the definitions provided within my prior response. Accordingly, SeaTalk cables have alway contained only the three previously specified leads. However, the interface cables supplied with some products may contain leads for not only supporting SeaTalk communications, but other communications protocols as well. The SeaTalk leads of such cables would typically have been connected to a SeaTalk cable via a SeaTalk junction box or via splicing the corresponding leads of each cable to one another. The latter would be documented within the corresponding product's installation/owner's manual.