Configure Modem emulator mode for a serial port

Modem emulator mode allows the device to act as a dial-up modem emulator for handling incoming AT dial-ins.

To change the configuration to match the serial configuration of the device to which you want to connect:

Choose the management interface you want to use to access your device. Click a dropdown for instructions.
Digi Remote Manager
1. Log in to Digi Remote Manager.
1. Navigate to the device's dashboard.
Web UI

Log in to your device's Web UI.

Admin CLI

Log in to your device's Admin CLI via an SSH client, Telnet client, or terminal emulator.
Configure the settings.
Menu instructions
1. Click to open the device's configuration menu.
  - In Digi Remote Manager, on the device dashboard, click Settings.
  - In the Web UI, click Serial Configuration or Device Configuration > Serial.
2. Click to expand the name of the port that you want to configure, for example, Port 1.
  The serial port is enabled by default. To disable, toggle off Enable.
3. For Mode, select Modem emulator. The default is Remote Access.
4. (Optional) For Label, enter a label that will be used when referring to this port.
5. For Baud rate, select the baud rate used by the device to which you want to connect. The default is 9600.
  - Max baud rate: 230400
  - Minimum baud rate: 50
    
    For a complete list, see Baud rate options.
6. For Data bits, select the number of data bits used by the device to which you want to connect. The default is 8.
7. For Parity, select the type of parity used by the device to which you want to connect. The default is None.
8. For Stop bits, select the number of stop bits used by the device to which you want to connect. The default is 1
9. For Flow control, select the type of flow control used by the device to which you want to connect. The default is None.
10. Enable Altpin to use the Altpin feature. Altpin is disabled by default. If you enable Altpin in EIA-232 mode, the DCD and DSR signals are swapped. This allows use of DCD with 8-wire cables. Altpin has no impact on 422 or 485 mode. For more information, see Serial connector pinout.
11. For Idle timeout, type the amount of time that the active session can be idle before the session is disconnected.
  
  Allowed values are any number of weeks, days, hours, minutes, or seconds, and take the format number{w|d|h|m|s}.
  
  For example, to set Idle timeout to ten minutes, enter 10m or 600s.
12. For Escape character, type the character to use in the escape sequence. Enter this character three times, followed by the escape delay and then an AT command to switch from data mode to command mode. The default is the plus sign (+).
13. For Escape delay, type the delay between the escape sequence and an AT command to switch from data mode to command mode. The default is 1s.
14. For Auto-answer rings, type the number of rings to wait before auto-answering. Enter 0 (zero) to disable auto-answering.
15. Command echo is enabled by default. Commands sent to the port are echoed back to the user. Select to disable this feature.
16. For Result codes, select the type of result code that are displayed as responses to commands. Options are:
  - None: No result codes are displayed.
  - Numeric: Numeric result codes are displayed.
  - Verbose: Result codes are displayed in English, for example: OK, ERROR, CONNECT. This is the default.
17. For Signaling, select the electrical signaling interface type used on this serial port:
  - RS-232. This is the default.
    Enable RTS Toggle if you want to enable RTS toggling during transmission on this serial port. If enabled, this setting overrides RTS\CTS flow control.
    For RTS Pre-delay, enter the amount of time RTS is asserted before starting data transmission. The time is measured in milliseconds. The default is 0ms.
    For RTS Post-delay, enter the amount of time RTS is deasserted before completing data transmission. The time is measured in milliseconds. The default is 0ms.
  - RS-422
    
    Enable Termination if you want to enable electrical termination on this serial port.
  - RS-485
    
    Enable Termination if you want to enable electrical termination on this serial port.
    
    Enable Full Duplex if you want to enable full duplex communication on this serial port.
    
    Enable Four Wire (or Four-Wire Communication) if you want to enable four-wire communication on this serial port. This option is disabled by default.
18. (Optional) Click to expand Phonebook and create dial strings that can be used to connect to remote servers.
  1. Click  to add a phone book entry.
  2. For Label, type a descriptive name for the phone book entry.
  3. (Required) For Dialstring, type the string to dial to connect to the remote server.
  4. (Required) For Connection destination, type the hostname or IP address of the remote server.
  5. (Required) For Connection port, type the TCP port of the remote server. Minimum is 1 and maximum is 65535.
19. Expand TCP connection to configure TCP connection for this serial port.
  1. To enable a TCP connection, click to toggle on Enable.
  2. For Port, type the TCP port for this service. The default is 4001.
  3. Expand Access control list to create a list of IP addresses, interfaces, and firewall zones from which this service may be accessed.
    
    To limit access to specified IPv4 addresses and networks:
    Click IPv4 Addresses.
    For Add Address, click .
    For Address, enter the IPv4 address or network that can access the device's service-type. Allowed values are:
    A single IP address or host name.
    A network designation in CIDR notation, for example, 192.168.1.0/24.
    any: No limit to IPv4 addresses that can access the service-type.
    Click  again to list additional IP addresses or networks.
    
    To limit access to specified IPv6 addresses and networks:
    Click IPv6 Addresses.
    For Add Address, click .
    For Address, enter the IPv6 address or network that can access the device's service-type. Allowed values are:
    A single IP address or host name.
    A network designation in CIDR notation, for example, 2001:db8::/48.
    any: No limit to IPv6 addresses that can access the service-type.
    Click  again to list additional IP addresses or networks.
    
    To limit access to hosts connected through a specified interface on the device:
    Click Interfaces.
    For Add Interface, click .
    For Interface, select the appropriate interface from the dropdown.
    Click  again to allow access through additional interfaces.
    
    To limit access based on firewall zones:
    Click Zones. By default, there are three firewall zones already configured: Internal, Edge, and IPsec.
    For Add Zone, click .
    For Zone, select the appropriate firewall zone from the dropdown.
    See Firewall configuration for information about firewall zones.
    Click  again to allow access through additional firewall zones.
  4. Toggle on Enable mDNS to enable Multicast DNS (mDNS) reporting for this service. This feature is disabled by default.
20. Expand Logging Settings to configure logging for this serial port.
  1. To enable logging, click to toggle on Enable.
  2. In the Log file name field, enter a descriptive name for the log file.
  3. For Log file size, type the size of the log file. When the log file reaches the size limit, the current file is saved and a new file is created. The default is 65536 bytes.
  4. Use the Enable remote logging option to enable serial data logging to remote servers. The serial data for the port is exported and sent to the remote server. The remote server configuration determines how the file is saved.
    
    Disabled: Serial data logging to remote servers is not performed. This is the default.
    
    Enabled: Serial data logging to remote servers is performed. The serial data for the port is exported and and sent to the remote server.
    
    Note When this feature is enabled, you must also have a syslog server configured for the device, which ensures that the log can be saved. To add a syslog server, click the wrench icon next to the Enable remote logging option or navigate to Device Configuration > System > Log > Server List.
  5. From the Type of data to log list box, specify the type of data that should be saved.
    
    Received
    
    Transmitted
    
    Both
    
    Both with arrows. This is the default.
  6. If you want to log the time at which date was received or transmitted, click the Timestamps toggle to Enable.
  7. If you want to log the data as hexadecimal values, click the Hexadecimal toggle to Enable.
    
    Note You can review the message log in the Serial Port Log page. See Review the serial port message log.
21. Click Apply to save the configuration and apply the change.
CLI instructions
1. At the CLI prompt, type config and then press Enter.
2. The serial port is enabled by default. To disable:
```
(config)> serial port1 enable false
(config)>
```
3. Set the mode:
```
(config)> serial port1 mode modem_emulator
(config)>
```
4. (Optional) enter a label that will be used when referring to this port.
```
(config)> serial port1 label <label>
(config)>
```
  where label is the label description, entered as a text string.
5. Set the baud rate used by the device to which you want to connect. The default is 9600.
```
(config)>serial port1 baudrate rate
(config)>
```
  - Max baud rate: 230400
  - Minimum baud rate: 50
    
    For a complete list, see Baud rate options.
6. Set the number of data bits used by the device to which you want to connect. The default is 8.
```
(config)>serial port1  databits bits
(config)>
```
7. Set the type of parity used by the device to which you want to connect.
```
(config)>serial port1 parity parity
(config)>
```
  Allowed values are:
  - even
  - odd
  - none: The default is none.
8. Set the stop bits used by the device to which you want to connect. The default is 1
```
(config)>serial port1 stopbits bits
(config)>
```
9. For Flow control, select the type of flow control used by the device to which you want to connect:
```
(config)>serial port1 flow type
(config)
```
  Allowed values are:
  - none: The default is None.
  - rts/cts
  - xon/xoff
10. Enable Altpin to use the Altpin feature. Altpin is disabled by default. If you enable Altpin in EIA-232 mode, the DCD and DSR signals are swapped. This allows use of DCD with 8-wire cables. Altpin has no impact on 422 or 485 mode. For more information, see Serial connector pinout.
```
(config)> serial port1 altpin true
(config)>
```
11. For Idle timeout, type the amount of time that the active session can be idle before the session is disconnected.
  
  where value is any number of weeks, days, hours, minutes, or seconds, and takes the format number{w|d|h|m|s}.
  
  For example, to set Idle timeout to ten minutes, enter either 10m or 600s:
```
(config)> path-param 600s
(config)> 
```
12. For Escape character, type the character to use in the escape sequence. Enter this character three times, followed by the escape delay and then an AT command to switch from data mode to command mode. The default is the plus sign (+).
```
(config)>serial escape_char <character>
(config)
```
13. For Escape delay, type the delay between the escape sequence and an AT command to switch from data mode to command mode. The default is 1s.
```
(config)>serial escape_delay number{w|d|h|m|s|ms}
(config)
```
  where number is any number of weeks, days, hours, minutes, or seconds, and takes the format number{w|d|h|m|s}.
14. For Auto-answer rings, type the number of rings to wait before auto-answering.
```
(config)>serial rings <value>
(config)
```
  where value is the number of rings.
  - Minimum: 0
  - Maximum: 255
  - 0: Enter 0 (zero) to disable auto-answering.
15. Command echo is enabled by default. Commands sent to the port are echoed back to the user.
```
(config)>serial echo {true|false|yes|no|1|0}
(config)
```
16. For Result codes, select the type of result code that are displayed as responses to commands. Options are:
```
(config)>serial result_codes {none|numeric|verbose}
(config)
```
  where the value can be:
  - None: No result codes are displayed.
  - Numeric: Numeric result codes are displayed.
  - Verbose: Result codes are displayed in English, for example: OK, ERROR, CONNECT. This is the default.
17. Set the signaling interface type used on this serial port:
  - rs -232. This is the default.
    Enable rts_toggle if you want to enable RTS toggling during transmission on this serial port. If enabled, this setting overrides RTS\CTS flow control:
    (config)> serial port1 rts_toggle true (config)>
    For rts_pre_delay, enter the amount of time RTS is asserted before starting data transmission. The time is measured in milliseconds. The default is 0ms:
    (config)> serial port1 "rts_pre_delay value (config)>
    For rts_post_delay, enter the amount of time RTS is deasserted before completing data transmission. The time is measured in milliseconds. The default is 0ms:
    (config)> serial port1 rts_post_delay value (config)>
  - rs -422
    
    Enable Termination if you want to enable electrical termination on this serial port.
  - rs -485
    
    Enable termination if you want to enable electrical termination on this serial port:
    (config)> serial port1 termination true (config)>
    
    Enable full_duplex if you want to enable full duplex communication on this serial port:
    (config)> serial port1 full_duplex true (config)>
    
    Enable four_wire if you want to enable four-wire communication on this serial port. This option is disabled by default.
    (config)> serial port1 four_wire true (config)>
18. (Optional) Create dial strings that can be used to connect to remote servers.
```
(config)>serial phonebook
(config)
```
19. Save the configuration and apply the change.
```
(config)> save
Configuration saved.
>
```
20. Type exit to exit the Admin CLI.
  Depending on your device configuration, you may be presented with an Access selection menu. Type quit to disconnect from the device.