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Phone Port Dead -- Again

Started by MarkE45, June 04, 2019, 07:44:22 PM

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MarkE45

Seems that for the last 6 years, my Obi blows up the phone port once a summer.  First in the Obi100, now with the Obi200.  Of course, it did it on the 1 year anniversary plus one day, so it's out of warranty. It always happens when there's a nearby lightning strike, and I've installed a fair amount of protection. I'm looking for suggestions on what else I can do.  First, my configuration:

The local DSL phone line runs through a surge protector to a DSL splitter/filter. A two line AT&T wireless base unit has line 1 plugged into the DSL filter's phone jack, and line 2 is plugged into the Obi200.  The DSL jack on the filter is plugged into the modem/router, and the Obi Ethernet port is plugged into an Ethernet switch daisy chained off the router.  The entire house is protected at the power service entrance by a Square D whole house surge protector.  The two line AT&T phone's power adapter, router and switch are all plugged into a UPS with surge protection.

So I think I'm covered for surges coming in from the phone and power lines.

Only other path I can think of is security cameras with outside wiring behaving like an antenna delivering a surge to the video recorder, which then passes through its Ethernet cable to the router and then on to the Obi.  But none of the other equipment malfunctions, and the Obi Ethernet port is fine as the device shows up in the ObiTalk dashboard.

I'm really at a loss to understand why the phone port appears to be so vulnerable, and what else I can do to protect it when there's a big flash/bang near my house.

Any suggestions would be appreciated.

Thanks

ps: I'm in Mexico, not the US, so getting replacements takes a while and is costly. I'm good with a soldering iron if anyone can point me to any simple component that might be replaced. I've checked the two fuses, F1 and F2, and they're OK.

SteveInWA

One obvious solution would be to not use the two-line phone, which might be passing the surge between its circuitry.  Plug a single-line cordless phone base station into the OBi's Phone port instead.

Another solution would be to add a better-quality telephone line surge protector.  Most of the ones that come with surge strips are junk.

See:  https://www.apc.com/shop/us/en/products/APC-ProtectNet-standalone-surge-protector-for-analog-DSL-phone-lines-2-lines-4-wires-/P-PTEL2

No, there are no user serviceable parts inside the OBi devices.  The telephone interface is a large-scale integrated circuit that you can't replace.

MarkE45

Quote from: SteveInWA on June 05, 2019, 05:44:45 PM
One obvious solution would be to not use the two-line phone, which might be passing the surge between its circuitry.  Plug a single-line cordless phone base station into the OBi's Phone port instead.

Another solution would be to add a better-quality telephone line surge protector.  Most of the ones that come with surge strips are junk.

I have a 2-line base station and 4 remote units.  Replacing that with two single line systems and 8 remotes isn't a practical option.  But thank you for the pointer to the APC unit.  I'll get one for the TelMex phone/DSL line and a second one for the Ethernet cable that enters the modem from the distant security camera video hub.

SteveInWA

Quote
that enters the modem from the distant security camera video hub.

Can you clarify exactly how this is physically connected?  In general, if this is a data connection between two free-standing buildings, and the equipment in both buildings is connected to AC power, it's a bad idea, as it can cause all sorts of electrical problems and exposures to surges.

MarkE45

In the main house, there's a cluster of electronics where the local landline enters -- UPS, surge protector, modem, 2-line phone base unit and the Obi200. In a storage room in another building is a UPS and video recorder with cables to eight outside cameras. About 75 feet of Cat-5 Ethernet cable connects the video recorder to the modem.  The two UPS's are on different breakers, but ultimately on the same line phase.  The power service entrance from the street has a house-wide Square-D surge protector.  Unlike most houses in Mexico that run only neutral and hot to the boxes, we actually have a green ground wire everywhere, tied to neutral at the service entrance, and #12 wire in the walls.

It's possible that the MOVs in the surge protectors are toasted. They're probably six years old, and we have a lot of lightning in the summer months.

drgeoff

MOVs do degrade each time they act to absorb an over-voltage.