A batch of scattered sites looks almost identical on paper: a router with a cellular SIM, a switch, an NVR, and seven to fifteen cameras behind them, with no fixed broadband within reach. What surfaces in the second month is a data plan running dry ahead of schedule and a bill showing one number for the whole site. One engineer put it plainly: overage almost always traces back to a camera or an NVR doing cloud sync in the background.
Answering how many cameras fit does not start with the spec sheet of a 4G cellular router or a 5G cellular router. The number is not set by the headline figure but by three sums: how much uplink exists, how much one stream consumes, and how many streams push outward at once.
Camera backhaul consumes uplink, while the largest number on a spec sheet is usually downlink; the two differ by an order of magnitude. LTE Cat4 sits around 50 Mbps of theoretical uplink, and field measurements often come in at half that. 5G SA opens the uplink by roughly an order of magnitude, though users on the same tower and antenna position pull measured values away from nominal ones.
Measurement beats the datasheet: run an uplink test in the busiest hour, take one reading morning, midday and evening, and keep the value that holds steady rather than the peak. Move the antennas outside the cabinet before measuring, since a metal enclosure eats uplink first. One more number belongs alongside: the monthly allowance of the plan. Enough bandwidth with not enough data still cuts off mid-month.
One formula applies directly: bitrate (Mbps) x seconds / 8 / 1024 = GB. A 1080p main stream typically lands between 2 and 4 Mbps, H.265 and H.264 differ noticeably, and a sub stream stays under 1 Mbps. Resolution, frame rate, codec and scene complexity all move it.
At 2 Mbps running 24 hours, one camera produces roughly 21 GB, close to 600 GB in a month. A dozen cameras pushed that way will exhaust any single SIM before month end. That formula is worth more than the megapixel count on the box; the bill is counted in bytes.
One router, seven cameras or twenty: the answer differs by which side the recording sits on.
Continuous backhaul: cameras push the main stream outward all the time and the far end watches live. Bandwidth decides. The count comes from measured uplink divided by per-stream bitrate, less a margin for headroom: single digits on 4G, more room on 5G, and a tighter bill.
Local recording: the NVR sits on the LAN side of the router, and traffic between cameras and NVR stays inside the site without touching the uplink. The far end only pulls a stream occasionally, so the number that matters is concurrency: how many streams get pulled at once, and whether each takes the sub stream or the main stream. A dozen or twenty cameras run fine under this architecture, with day-to-day uplink close to zero.
The condition is that the NVR itself stays under control: cloud sync and cloud backup running in the background are often the largest single flow at a site, and leaving them on brings the bill of the first architecture along with it.
One more kind of overload has nothing to do with bandwidth. Seven to fifteen cameras far exceeds the ports built into a cellular router, so the site needs a switch, usually a PoE model that also shortens cabling by drawing power nearby. Running out of ports is a physical limit, and no faster module fixes it.
Keep the main stream local and let the far end pull only the sub stream, counting streams by concurrency rather than by the camera total. Switch to motion detection or alarm-triggered upload, and push replay and bulk downloads into a night window. Turn off NVR cloud sync, or narrow it to alarm clips; where a cloud copy is required, pin the destination address and deny everything else by default. Where fixed broadband can reach the site, make the wired link primary and drop cellular to backup, set the data threshold at 70 to 80 percent of the allowance, and route the overage alert to email and SMS rather than waiting for the invoice.
The USR-G809s matches sites with many devices and more than ten cameras: 2 ports configurable as WAN or LAN, 6 LAN ports and 2 SFP slots, one of which shares with a copper port, all RJ45 at Gigabit, DIN rail mounting, wide-range DC 9-60 V input with reverse polarity protection. Cameras and NVR both land on the LAN side, so local traffic never consumes uplink; an SFP slot brings a point several hundred meters away back into the site.
The USR-G816 fits locations with no broadband where several streams need watching at once from a distance: 5G SA and NSA dual mode, 1 Gigabit WAN port configurable as LAN plus 3 Gigabit LAN ports, dual SIM with the second available as an embedded eSIM, an RS232/RS485 terminal block that takes a data logger and saves a separate box, three alert classes including data overage, and automatic failover to backup when the primary link drops.
The USR-G806w suits small cabinets where space is tight: 104 x 102 x 28 mm, DIN rail or wall mounting, three Fast Ethernet ports with one WAN port configurable as LAN, wide-range DC 9-36 V input with reverse polarity protection, -20 to 70 degrees Celsius. The underestimated part at this tier is local tooling: daily and monthly traffic charts that forecast monthly usage, live sessions showing which endpoints reach outward, QoS precise flow control and per-terminal flow control that clear the path for critical traffic, policy routing that splits public and private network data across different exits, and Ping, Traceroute, Nslookup and packet capture on the device itself.
The first is the steady measured uplink value, recorded together with antenna placement. The second is the bitrate and the number of continuously uploading streams, from which monthly usage is estimated before the SIM is activated. The third is the recovery time measured with a stopwatch after unplugging the primary link, plus confirmation that the NVR kept writing to its local disk during the wait. All three go into the handover document, so the following year has a baseline.
How many cameras a router carries is not a fixed number. Whether the uplink is enough decides how many streams can run continuously; which side the recording sits on decides how much uplink gets used day to day; whether the NVR is quietly syncing in the background decides whether the month-end bill doubles. Work through the three sums before choosing between a 4G cellular router and a 5G cellular router. Reversing that order costs more on bandwidth and keeps the overage going.
1. Is speed the only difference between a 5G cellular router and a 4G cellular router?
No. Uplink capacity is the difference that surveillance feels most directly: LTE Cat4 sits around 50 Mbps of theoretical uplink while 5G SA uplink can be an order of magnitude higher, and the gap widens when several video streams go out at once. Port speed, dual SIM redundancy, and the power and temperature range also differ. Where a site records locally and only pulls a stream occasionally, 4G is entirely sufficient, and the budget saved is better spent on the data plan and a spare unit.
2. So how many cameras can one 4G or 5G router actually carry?
It depends on how many streams leave at the same time. Counted as continuous upload, the number is roughly measured uplink divided by per-stream bitrate, with a margin discounted. Counted as local recording with the far end pulling a stream occasionally, twenty cameras on site are manageable, because day-to-day uplink sits close to zero. Once the camera count exceeds the ports on the router, add a switch first; that is a physical limit, unrelated to bandwidth.
3. With recording already on a local NVR, how much uplink is still needed?
Concurrency bandwidth, not total bandwidth. How many streams get pulled at once, and whether each takes the sub stream or the main stream, multiplied together give the uplink peak. Most sites have one or two streams being watched at any moment, and a sub stream runs under 1 Mbps each. What saturates the uplink without warning is background cloud sync and footage replay downloads; either disable them or schedule them into a night window.
4. The SIM keeps running out early. Where does the check start?
Start with whether the NVR or the cameras are doing cloud sync or cloud backup in the background, activity that never shows up as someone watching a feed. Then set a loose cap on the suspected device by address range or MAC, run two days and see whether the curve changes; if nothing shifts, disconnect units one at a time and compare. Daily and monthly traffic bar charts together with live sessions usually identify the specific device before the invoice arrives.
5. With no public IP, can a site's cameras still be viewed remotely?
Cellular networks usually hand out private addresses, so connections initiated from the public side cannot get in and port forwarding is a dead end. The approach runs the other way: the router initiates an encrypted tunnel outward, or a companion management platform opens the device from the far end, with no inbound port exposed at the site. Once the tunnel is up, traffic is permitted address by address and port by port, with everything else denied by default.
6. What does dual SIM do for a surveillance site?
First, changing plan or carrier does not mean changing hardware. Second, when the tower serving one SIM is congested or fails, the router can switch to the other automatically. Two SIMs from different carriers also sidestep local coverage gaps. Whether data during the switch is buffered on the device or replayed from the platform is worth confirming once during commissioning rather than assuming it repairs itself.
7. Does footage get lost when the link drops or switches over?
Footage on a local NVR is unaffected by an uplink outage, since cameras reach the NVR over switching inside the site. What needs confirming is whether the local disk kept writing during those tens of seconds of switchover, and whether alarm clips were filled in afterward. Unplugging the primary link once with a stopwatch is the acceptance test for that item.
8. How does an industrial cellular router differ from a home router in surveillance work?
The difference shows up during the hours nobody is watching. The industrial side brings a metal housing, wide-range input with reverse polarity protection, a wide operating temperature range, DIN rail or wall mounting, hardware and software watchdogs that reset automatically, and three alert classes covering offline status, weak signal and data overage that push out on their own. Home equipment is designed for intermittent use in occupied spaces; left in an outdoor cabinet year round, power supply and thermal issues
