I want to connect to the Internet small office where docsis (internet over tv cable) is used as WAN.
For similar tasks but other WANs (adsl, dial-up) I used 800 series. But now I can't find anything in this series to solve my issue.
There is 815 but it has no wi-fi.
I can use cable modem that my ISP gave to me: this modem acts as bridge so I can use router with FE-based WAN but it is better to have one device instead of two.
Does there is some router may help me?
Yeah, I do not think there is another Cisco 900 series router with integrated broadband cable card. However, the newer Scientific Atlanta DPC3925 and DPC3825 are designed not just as a modem but as residential gateways. This means they have a router function which allows your devices to log onto a private wifi network and the modem bridges them into the DOCSIS backhaul.
The problem with the DPC3925/3825 is that they are designed to be exclusively service-provider operated so you'll have to find an ISP which has this modem and is serving a eRouter type service.
There are some used uRB900 routes on the net but none of them has 802.11 probably because they are too old. Cisco itself recomends to use LinkSys instead. Looks like LinkSys replaces ios-based routes in SOHO solutions because DOCSIS primary used at home..