2 fish finders 1 transducer using SB646 and wiring

[ztugdriver]

Hello
So my idea was to use my currently installed B258-14HB Hummingbird transducer that has a match cable to Furuno 10 pin. Its connected to a GP18070F now. Im upgrading to a FCV-800 and a GP1971F. Id like to use just 1 transducer. I found the SB646 and it looks like it would work. Id never need to have both head units displaying the depth the GP1971F would just be a back up sounder and Chart Plotter. My question is anyone do this? any thoughts?

Also the transducer I have according to the tag says its a B258-14HB / 41-456-2-01. It comes up as a Hummingbird xducer on the Airmar site and has no wiring diagram. I may need it when I install the SB646 depending on where I locate the box. I have no wiring info on the xducer and can't find it on Airmar site. Do any of you have a diagram? I just realized that the transducer probably has a 9 pin mix and match cable end on it already is that correct?

Thanks in advance

 

[Johnny Electron]

I never recommend switch boxes because people tend to switch while the units are turned ON. This results in load being suddenly tossed onto an unloaded sounder and vice versa. It is a good way to damage the connected sounders. If one is 100% careful and turn then both off each time you switch and don't turn on the one without something connected, then it can work. Reality is someone ends up in a rush or a bad brother-in-law comes along and makes it an expensive ordeal. Not sure that the hummingbird has the same impedance or can be used. You would need to consult directly with Gemeco/Airmar on that.

 

[ztugdriver]

Thank you so much for your response. Appreciate the input. Ive been going down rabbit holes trying to figure this setup out. I do have a potential solution to possibly damaging a head unit by 1 disabling the sounder xmit on the GP1971 and 2 hiding the switch so no one knows where it is. Im only using the SB646 because I have it. I did more research called Airmar and found that my B258 is a mix and match transducer. Its has a 10 pin Furuno cable. Its working great connected to my GP1870F. My biggest question is when I go and hardwire these units into the SB646 Im going to need an extra 10 pin Furuno pigtail and when I look them up online some are missing pins 5&6. Are they just stock photos or does the Air 033-333 pigtail really come with enough pins in it to connect all 7 wires I need. The diagram I have says I would need pin 5 for XID. Im wondering if Im relying too much on the photos these suppliers use on the website and if its just a stock photo? Im trying to avoid buying the wrong cable. Id like to keep all the functionality if possible.
Thanks for the help.

 

[Johnny Electron]

The wiring of the pigtail cable shows all wires are available including pin 5.

 

[ztugdriver]

Impressive don’t know how you found that but thank you for the info. I’m pretty sure I was over thinking it but with the price of things I just wanted to make sure. Thanks again.