diff --git a/docs/configuring-playbook-matrix-sms-bridge.md b/docs/configuring-playbook-matrix-sms-bridge.md
index 00aaecec..4a486774 100644
--- a/docs/configuring-playbook-matrix-sms-bridge.md
+++ b/docs/configuring-playbook-matrix-sms-bridge.md
@@ -13,7 +13,7 @@ playbook configuration:
 
 ```yaml
 matrix_sms_bridge_enabled: true
-matrix_sms_bridge_gammu_modem: "/path/to/modem"
+matrix_sms_bridge_gammu_modem: "/dev/serial/by-id/myDeviceId"
 # generate a secret passwort e.g. with pwgen -s 64 1
 matrix_sms_bridge_database_password: ""
 # (optional) a room id to a default room
@@ -22,6 +22,8 @@ matrix_sms_bridge_default_room: ""
 matrix_sms_bridge_gammu_reset_frequency: 3600
 # (optional) group with unix read and write rights to modem
 matrix_sms_bridge_modem_group: 'dialout'
+# (optional) cgroup major number to allow access to devices, that gets reconnected (e.g. due to reset)
+matrix_sms_bridge_cgroup_major_number: '188'
 ```
 
 
diff --git a/roles/matrix-sms-bridge/defaults/main.yml b/roles/matrix-sms-bridge/defaults/main.yml
index 610b8f46..0bbdc5a0 100644
--- a/roles/matrix-sms-bridge/defaults/main.yml
+++ b/roles/matrix-sms-bridge/defaults/main.yml
@@ -48,6 +48,7 @@ matrix_sms_bridge_homserver_domain: "{{ matrix_domain }}"
 matrix_sms_bridge_default_room: ''
 
 matrix_sms_bridge_gammu_modem: ''
+matrix_sms_bridge_cgroup_major_number: '188'
 matrix_sms_bridge_modem_group: 'dialout'
 matrix_sms_bridge_gammu_reset_frequency: 0
 
@@ -110,7 +111,7 @@ matrix_sms_bridge_configuration: "{{ matrix_sms_bridge_configuration_yaml|from_y
 
 matrix_sms_bridge_gammu_configuration: |
   [gammu]
-  Device = /dev/ttyModem
+  Device = {{ matrix_sms_bridge_gammu_modem }}
   LogFile = /data/log/gammu.log
   debugLevel = 1
 
diff --git a/roles/matrix-sms-bridge/templates/systemd/matrix-sms-bridge.service.j2 b/roles/matrix-sms-bridge/templates/systemd/matrix-sms-bridge.service.j2
index cf8ab9fe..bb43a4b8 100644
--- a/roles/matrix-sms-bridge/templates/systemd/matrix-sms-bridge.service.j2
+++ b/roles/matrix-sms-bridge/templates/systemd/matrix-sms-bridge.service.j2
@@ -29,7 +29,8 @@ ExecStart=/usr/bin/docker run --rm --name matrix-sms-bridge \
 			-v {{ matrix_sms_bridge_config_path }}:/config:z \
 			-v {{ matrix_sms_bridge_data_path }}:/data:z \
 			-v {{ matrix_sms_bridge_config_path }}/gammu-smsdrc:/etc/gammu-smsdrc:z \
-			--device {{ matrix_sms_bridge_gammu_modem }}:/dev/ttyModem \
+			--device-cgroup-rule='c {{ matrix_sms_bridge_cgroup_major_number }}:* rmw' \
+			--device {{ matrix_sms_bridge_gammu_modem }}:{{ matrix_sms_bridge_gammu_modem }} \
 			{% for arg in matrix_sms_bridge_container_extra_arguments %}
 			{{ arg }} \
 			{% endfor %}