In Trunk mode the PVID is VLAN 1 by default. You can this by entering the command [tag:switchport] trunk native vlan {vlan number}. If the Cisco is configured to accept and send tagged packets, and has an IP address in the VLAN 20 subnet, it should be able to communicate with other devices in VLAN 20. 
Hi...  We are setting up a new 5524 switch i have untagged access ports on vlan 20 and trunked ports where vlan 20 i allowed. I set up one computer on the access port one on the trunk port same ip net...cant ping beween them. I'm no switch expert, so I wonder what I have missed,. I did the same thing on an older dell 3524 and it works directly... Here is the config the port i tried to ping beween is port 6 and port 10 (Another thing how how do i remove: switchport mode trunkswitchport access vlan none) Any help would be greatly appriciated! interface vlan 1 ip address 88.131.90.252 255.255.255.240!interface vlan 5 name "CPE TDC"!interface vlan 6 name "outside Tele2"!interface vlan 7 name "Outside Telenor"!interface vlan 8 name "TDC Multivrf"!interface vlan 20 name TDC-CISCO-LAN![0mMore: , Quit: q or CTRL+Z, One line: interface vlan 21  name "FW inside" ! interface vlan 99  name "FW sync" ! interface gigabitethernet1/0/1  description CPE1  switchport access vlan 5 ! interface gigabitethernet1/0/2  description CPE2  switchport access vlan 5 ! interface gigabitethernet1/0/3  description df  spanning-tree portfast  switchport mode trunk  switchport access vlan none ! interface gigabitethernet1/0/4  description upps-cb2 [0mMore: , Quit: q or CTRL+Z, One line: spanning-tree portfast  switchport mode trunk  switchport access vlan none ! interface gigabitethernet1/0/5  description upp-ccm1  spanning-tree portfast  switchport access vlan 20 ! interface gigabitethernet1/0/6  description upps-ccm2  spanning-tree portfast  switchport access vlan 20 ! interface gigabitethernet1/0/7  description tdc-multivrf1  switchport access vlan 8 ! interface gigabitethernet1/0/8  description TDC-multivrf2  switchport access vlan 8 ! [0mMore: , Quit: q or CTRL+Z, One line: interface gigabitethernet1/0/9  description Upps-cb-tq03  spanning-tree portfast  switchport mode trunk ! interface gigabitethernet1/0/10  description upps-cb-tq04  spanning-tree portfast  switchport mode trunk ! interface gigabitethernet1/0/11  description tele2-outside  switchport access vlan 6 ! interface gigabitethernet1/0/12  description tele2-outside  switchport access vlan 6 ! interface gigabitethernet1/0/13  description telenor-outside  switchport access vlan 7 ! [0mMore: , Quit: q or CTRL+Z, One line: interface gigabitethernet1/0/14  description telenor-outside  switchport access vlan 7 ! interface gigabitethernet1/0/15  description Mot-Upps-fw-tq01-inside  switchport mode trunk ! interface gigabitethernet1/0/16  description mot-Upps-fw-tq02-inside  switchport mode trunk ! interface gigabitethernet1/0/17  description FW-sync  switchport access vlan 99 ! interface gigabitethernet1/0/18  description FW-sync  switchport access vlan 99 ! interface gigabitethernet1/0/19  description Mot-Upps-fw-tq01-outside [0mMore: , Quit: q or CTRL+Z, One line: switchport mode trunk ! interface gigabitethernet1/0/20  description Mot-Upps-fw-tq02-outside  switchport mode trunk ! interface gigabitethernet1/0/22  description FW-Sync  switchport access vlan 99 ! interface gigabitethernet1/0/23  description Mot-Upps-FW-tq01-outside  ip address 192.168.11.1 255.255.255.0  switchport mode trunk ! interface gigabitethernet1/0/24  description Mot-AIN-LAN-SW  switchport access vlan 20 ! ip route 0.0.0.0 0.0.0.0 88.131.90.241  [0mMore: , Quit: q or CTRL+Z, One line:   VLAN information  Vlan Name Tagged Ports UnTagged Ports Type Authorization ---- ------------ ------------------ ------------------ --------- -------------  1 1 gi1/0/3-4, Default Required  gi1/0/9-10,  gi1/0/15-16,  gi1/0/19-21,  gi1/0/23,  gi1/0/25-48,  te1/0/1-2,  gi2/0/1-48,  te2/0/1-2,  gi3/0/1-48,  te3/0/1-2,  gi4/0/1-48,  te4/0/1-2,  gi5/0/1-48,  te5/0/1-2,  gi6/0/1-48,  te6/0/1-2,  gi7/0/1-48,  te7/0/1-2,  gi8/0/1-48,  te8/0/1-2,Po1-32  5 CPE TDC gi1/0/3-4, gi1/0/1-2 permanent Required [0mMore: , Quit: q or CTRL+Z, One line: gi1/0/9-10,  gi1/0/15-16,  gi1/0/19-20,  gi1/0/23  6 outside gi1/0/3-4, gi1/0/11-12 permanent Required  Tele2 gi1/0/9-10,  gi1/0/15-16,  gi1/0/19-20,  gi1/0/23  7 Outside gi1/0/3-4, gi1/0/13-14 permanent Required  Telenor gi1/0/9-10,  gi1/0/15-16,  gi1/0/19-20,  gi1/0/23  8 TDC Multivrf gi1/0/3-4, gi1/0/7-8 permanent Required  gi1/0/9-10,  gi1/0/15-16,  gi1/0/19-20,  gi1/0/23  20 TDC-CISCO-LA gi1/0/3-4, gi1/0/5-6,gi1/0/24 permanent Required  N gi1/0/9-10,  gi1/0/15-16, [0mMore: , Quit: q or CTRL+Z, One line: gi1/0/19-20,  gi1/0/23 
Dell powerconnect 5524 cant ping between access port and trunk port