It is a Spectrum supplied Arris TM1602A MTA. It handles telephone and internet. It is an “Embedded Multimedia Terminal Adaptor”. Many modems also have the ability to be a router. This appears to be just a dumb modem. I found the manual online and this doesn’t do any router functions, only a modem.
So, given that it can’t do DHCP, port forwarding, NAT… I guess you could consider that bridge mode.