Improperly selected or incorrectly configured network elements are the most common cause of problems with the POS system. These may include communication problems between the cash register and other devices, such as payment terminals or Mobile Waiters, or failures during card payments. Alternatively, completed cash register transactions are not transmitted to Dotypos Cloud in real time. A stable and optimally configured network in the establishment is therefore very important for the functioning of Dotypos and its POS peripherals.

The types of networks and security supported by Dotypos devices are clearly shown in this table.

Warning

The quality of network coverage of the premises and the appropriate network setup are solely the responsibility of the customer and Dotypos is not responsible for them. This chapter serves as a guide to the optimal / recommended network setup for the needs of the Dotypos POS system and Dotypay payment terminals.

How to recognize an improperly configured network?

An improperly built or configured network or an unstable internet connection manifests itself in the following symptoms:

•In Dotypos, the cloud icon on the main screen indicating the connection to Dotypos Cloud lights up red. This means that synchronization between the cash register and Dotypos Cloud is not taking place.

•The LAN / Wi-Fi receipt or order printer does not print, or printing drops out irregularly.

•Mobile Waiters have long response times, you have to wait several seconds to move or close a bill, or they lose connection when moving around the establishment (e.g. between the restaurant and the outdoor seating area).

•Card payments do not go through connected payment terminals.

•Dotypay payment terminals report a connection error to the transaction center during payment.

•During heavy traffic, the entire POS system experiences long response times. Problems also occur irregularly, only at certain times of the day or only in certain parts of the establishment.

If your establishment is experiencing the problems described above when using the Dotypos cash register, Mobile Waiters or payment terminals, pay attention to the recommended network setup described below:

•Steps for the recommended network setup

oChecklist

oQuick check using a mobile hotspot

oVerifying network throughput with the ping command

oRestoring factory settings of active network elements

•Network environment requirements for the Dotypos POS system

oSeparate standalone wireless network for cash registers and POS peripherals

oWireless network security

oCable connection

oWireless network band and channel

oSignal strength

oStatic IP addresses / DHCP server

oRouter and active network elements

oInternet connection

oCommunication and ports

oAndroid device settings

•Overview of addresses and ports

•Network quality parameters

•Dotypay payment terminals

•Roaming of devices between access points (AP)

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Steps for the recommended network setup

Checklist

•POS network separated from the customer network, without active client isolation

•Network security WPA2-Personal with AES, or WPA2/WPA3 mixed mode

•Recommended band 2.4 GHz, recommended fixed channel 1, 6 or 11, channel width 20 MHz, no band steering

•Signal strength of at least −65 dBm in all places where Mobile Waiters and payment terminals are used

•Printers and stationary cash registers connected by cable

•Each device has a static IP address, no conflicts, everything in the same subnet, a single DHCP server

•Random MAC address and battery optimization disabled on the devices, correct and synchronized date and time

•Network elements from a single manufacturer, no repeaters

•Correct and synchronized time and date on the router, working DNS

•Internet connection of at least 10 Mb/s download / 2 Mb/s upload

•The firewall does not block servers and ports for Dotypos and Dotypay

•Ping between the cash register and the payment terminal / Mobile Waiter without packet loss for at least 3 minutes

Quick check using a mobile hotspot

The easiest and fastest way to verify that POS system problems are not caused by the network in your establishment is to use a hotspot. Turn on the hotspot on any mobile phone or tablet with data services and temporarily connect the cash register and other POS peripherals to this hotspot. If everything works properly on the hotspot, you need to focus on adjusting the network at your establishment. The recommended solution in this case is to restart or reset all network elements to their factory default settings and then verify the communication.

Verifying network throughput with the ping command

You can verify the current network throughput with the ping command left running for at least 3 minutes, ideally 10 minutes (ping -n 600 X.X.X.X). Run the ping from the cash register or from your own computer, e.g. to the IP address of the payment terminal, LAN printer or Mobile Waiter. Compare the result with the values in the table below. If the problems occur only occasionally, run the test at the time when they usually occur, for example during peak hours.

Restoring factory settings of active network elements

A good starting point for an optimal network configuration is the factory settings of the network elements. Ideally, start the network configuration this way. If your routers are already configured and the communication of POS devices does not work, back up the router configuration and then restore their factory settings. Then verify the operation / communication of the individual POS devices. If they work after the factory reset of the routers, gradually apply any preferred changes step by step. After each partial change of the router settings, verify again that the communication works without problems throughout the establishment.

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Network environment requirements for the Dotypos POS system

Step 1

Separate standalone wireless network for cash registers and POS peripherals
We highly recommend using separate active elements (routers). For example, one for the customer network and the other for the Dotypos POS system. The network elements used must have sufficient capacity for both networks. We do not recommend sharing one network (and one router) by staff and customers, primarily for capacity and security reasons. An alternative is separation using VLANs on professional network equipment. The POS network must not have client isolation enabled (AP isolation / Client isolation) and must not be set up as a guest network (Guest network). Otherwise the devices would not see each other and the cash register would not communicate with the terminal, printer or Mobile Waiter. Each POS device, including Mobile Waiters, should have only one network saved that it connects to. Remove the other network configurations from the device. Do not use a login page (Captive portal) or connection time limits on the POS network.

Step 2

Wireless network security
Protect both networks with WPA2-Personal with AES (CCMP) encryption. Do not use an open network, WEP or WPA/WPA2 with TKIP. You can also use WPA2/WPA3 mixed mode. WPA3 alone is not supported.

Step 3

Cable connection
Receipt and order printers (kitchen tickets) connected by an uninterrupted Ethernet cable directly to the router or switch. We also recommend connecting stationary cash registers by cable, if possible.

Step 4

Wireless network band and channel
For maximum compatibility, especially with older devices, we recommend a separate POS Wi-Fi network in the 2.4 GHz band. The 5 GHz band can be used if all connected devices support it and sufficient coverage is ensured throughout the establishment. Ideally, do not combine bands under the same network name (SSID). So-called band steering can cause devices to jump between bands and short outages. When combining bands, you must verify continuous connection of the POS devices while they are moving. If the router broadcasts the network in both the 2.4 GHz and 5 GHz bands, it is a good idea to name the two networks differently (e.g. Net_2G and Net_5G) and connect the POS devices and peripherals to only one of them. In the 2.4 GHz band, use a channel width of 20 MHz and when planning multiple access points (AP), prefer channels 1, 6 and 11. Do not choose the channel based only on the number of surrounding networks. Their strength, load and other sources of interference are also important.

Step 5

Signal strength
In all places where Mobile Waiters and payment terminals are used (including the outdoor seating area, lounge or storeroom), the signal strength should be at least −65 dBm. A signal between −66 and −75 dBm is borderline, weaker than −75 dBm is insufficient. Verify the coverage by walking through the entire establishment with a Mobile Waiter or payment terminal. Do not place Wi-Fi routers or access points (AP) in closed metal cabinets, under the counter or next to a microwave oven (it can significantly interfere with the 2.4 GHz frequency). The devices should be placed as high as possible with free space around them.

Step 6

Static IP addresses / DHCP server
Each POS device (cash register, printer, payment terminal, Mobile Waiter, customer display) must have a static IP address. The most reliable method is IP address reservation based on the MAC address of the device on the router's DHCP server. Only one DHCP server should be active in the network. Set any additional routers used only to extend the Wi-Fi signal to access point (AP) mode, without their own DHCP server and NAT. When setting the IP address manually, also fill in the correct subnet mask, default gateway and DNS servers. If you set a static IP address directly in the device, choose one outside the DHCP server range to avoid an address conflict. On Android devices, disable the random MAC address (MAC randomization) for the POS network, otherwise the IP reservation will not work. All POS devices must be in the same network (subnet). The terminal must not be connected e.g. via mobile data or to the guest network.

The general procedure for setting a static IP address on the cash register is described in this chapter. It is not possible to set your own IP address directly on the Dotypay terminal, you need to make a reservation based on the MAC address of the device.

Step 7

Router and active network elements
Do not mix network elements from different brands and suppliers. Always use network devices (routers, APs) from a single manufacturer. Do not use wireless Wi-Fi repeaters (range extenders), they dramatically reduce network stability. For larger establishments, always use access points (AP) connected to the main router by a fixed cable. Switch the router from your provider to bridge mode, or the second router to AP mode. If the devices use automatic discovery via mDNS / DNS-SD, the network must not block the relevant multicast communication. Active network elements must have the correct date and time set with synchronization over the internet (NTP server).

Step 8

Internet connection
The recommended connection speed is at least 10 Mb/s download and 2 Mb/s upload, during normal operation including the separate customer network. DNS servers must respond quickly and reliably (under 100 ms).

Step 9

Communication and ports
The firewall on the router must not block outgoing communication to the servers and ports listed in the tables below, nor local communication between the cash register and the terminal on port 7500. The cash register communicates with Dotypos Cloud on ports 80, 443 and 8080 by default. The availability of the Dotypos API at api.dotykacka.cz is also important. If you use a firewall with encrypted traffic inspection (SSL/TLS inspection, content filtering or geo-blocking), set up an exception for these servers.

Step 10

Device settings
Disable battery optimization and power saving mode for the Dotypos and Dotypay apps. In the Wi-Fi settings, disable Wi-Fi sleep when the screen is off (if the device supports it). The device must also have the correct date and time set.

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Overview of addresses and ports

Dotypos and Dotypos Cloud
Service	Target	Port	Protocol
Dotypos / Dotypos Cloud	api.dotykacka.cz	80, 443, 8080	TCP

Dotypay payment terminals
Service	Target	Port	Protocol
Solitea Pay payment network	193.33.23.54	37690	TCP/SSL
Dotypay portal	portal.dotypay.com	443	TCP (HTTPS)
Backup IP addresses of the Dotypay portal	15.197.213.19, 3.33.254.128	443	TCP (HTTPS)
Push notifications	sqs.eu-central-1.amazonaws.com	443	TCP (HTTPS)
Local communication with the cash register	IP address of the terminal in the LAN	7500	TCP

Electronic Registration of Sales – EET 2.0
Service	Target	Port	Protocol
Financial Administration	https://trzbyeet.gov.cz/eet/services/EETServiceSOAP/v4	80, 443	TCP (HTTPS/TLS)

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Network parameters

Recommended values
Parameter	Meets	Warning (borderline)	Does not meet
Wi-Fi signal strength	≥ −65 dBm	−66 to −75 dBm	< −75 dBm
Packet loss in the establishment network	0 %	> 0 % to 1 %	> 1 %
Average response time (ping) in the establishment network	< 20 ms	20–50 ms	> 50 ms
Maximum response time in the establishment network	< 100 ms	100–300 ms	> 300 ms
Response time variation (jitter)	< 10 ms	10–30 ms	> 30 ms
Internet speed download / upload	≥ 10 / 2 Mb/s	5–10 / 1–2 Mb/s	< 5 / < 1 Mb/s
Response time to api.dotykacka.cz	< 100 ms	100–300 ms	> 300 ms
DNS resolution time	< 100 ms	100–500 ms	> 500 ms or error

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Dotypay payment terminals

•Connect the payment terminals to the same network as the cash register. A terminal on mobile data or in the guest network cannot communicate with the cash register.

•Assign a static IP address to the terminals (see step 6 above). Then pair the terminals with the cash register.

•Make sure that the firewall does not block the payment network and the Dotypay portal (see the table of ports above).

Tip

You can find the procedure for finding out the assigned IP address on the Dotypay payment terminal here. The general procedure for connecting another supported payment terminal to the cash register, including setting a static IP address on the router, is described in this chapter.

Roaming of devices between access points (AP)

If you use multiple access points (AP) or a mesh system to cover your establishment and there is a delay when switching from one AP to another, try setting the minimum signal strength at the level of the individual APs (Minimum RSSI). The optimal stable signal value is around −70 dBm, but it always depends on the specific network installation. Ideally, set the Minimum RSSI only after verifying the coverage overlap of neighboring APs. The threshold value for switching to another AP is usually −65 dBm. A threshold that is too high can also cause devices to disconnect. Verify the specific value by measuring and testing while moving around the establishment. This is explained, for example, in this article for the UniFi system. All APs must broadcast the same network (same SSID, password and security) and neighboring APs should use different channels (1, 6, 11).

Warning

To connect the Dotypay terminal to a hidden network, go to the list of Wi-Fi networks by long-pressing the Wi-Fi network icon in the top bar, or tap MORE SETTINGS there. After entering the network name, selecting the security type and entering the password, continue by tapping Advanced options. Here, set the Hidden network item to Yes and save the settings.

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