Model :

Hardware Version :

Firmware Version :


Every afternoon between 3 & 5:00, my users (at remote site) say that they make or receive calls where the caller can hear them, but they can't hear the caller.
The phone guy thinks it has something to do with SPI (stateful packet inspection).

- Toshiba VOIP system (not sure of model)
- VPN with TL-ER604W routers on both ends
- Firmware 1.1.0 Build 20151021 Rel.72279s on both routers
- Cable modems from same ISP on both ends

I don't see anything in the router logs around that time.

Something I just found while typing this:
- Router times
- HQ site: UTC+08 Shows 5:15:05 Thu
- Remote site: UTC -5 shows 17:15:31 Wed

Maybe this is the problem. What about SPI? Does the ER604W do SPI?