e125 - VHF DSC Intergration via Seatalk

[Chuck - Raymarine - Moderator]

Matt,

Q1. I was planning to link the VHF NMEA0183 input and output to the E85001 interface to save running a dedicated NMEA cable to the e125, but looking through its manual, it does not appear to support the DSC/DSE sentences for DSC polling. So I don't think this is an option, is that correct?
A1. You are indeed correct in your belief that the E85001 PC/SeaTalk/NMEA 0183 does NOT support bridging of DSC & DSE NMEA 0183 sentences. Should the VHF radio not additionally be an AIS receiver, then it would be recommended that the VHF radio be interfaced directly to the NMEA 0183 leads of the MFD's Power/NMEA 0183/Video Input Cable. However, should the VHF radio additionally be an AIS receiver, then it would typically be recommended that the VHF radio/AIS receiver be interface to the MFD via a SeaTalkng/NMEA 2000 backbone to support any future expansion of the system. Should this not be a concern (Note: MFDs will not bridge AIS data received from a NMEA 0183 source to SeaTalkng/NMEA 2000), then it would be recommended that the VHF radio/AIS receiver be interface to the MFD via direct NMEA 0183 communications.

Q2. Next I thought of using the NMEA input & output on the ST60+ Graphic display near the VHF again to save running a dedicated cable. However I read on another thread that the Seatalk to Seatalk ng Converter is not designed to handle DSC/DSE polling, so I am thinking that this will not work to get the communication between the MFD & the VHF either. Is that correct?
A2. You are indeed correct in your belief that the ST60 Graphic does NOT support bridging of DSC & DSE NMEA 0183 sentences.

Q3. Which leave me my last option which is to wire the NMEA inputs outputs directly to the e125 4800 baud port1. Howver reading my manual, the maximum distance to extend the NMEA port cables is 5m and my cable runs will be in the order of 7m. Will this still work? If not are there any other options?
A3. Per the NMEA 0183 INSTALLATION AND OPERATING GUIDELINES, "Interface cables shall be kept as short as possible and shall not exceed 150 feet" ... for NMEA 0183 ports utilizing RS-422 communications. The NMEA 0183 ports of a/c/e/eS/gS-Series MFDs utilize single ended RS-232 communications, which is typically limits cable lengths to 5m, particularly if used for 38400 BAUD data rate. As you will not be extending significantly longer and the port will be configured for 4800 BAUD communications, you will likely find that extending the cable using marine grade twisted pair signal cable to 7m will work satisfactorily. If not, then it would be necessary to install a NMEA 0183 expander/RS422 converter to communications over the required distance.