Yes on asa this is possible.
Let's assume your outside name is outside and acl attached to it called outside_access_in
Here a config sample (sorry if there are some typos, I'm writing this down from my smartphone):
object service PABX-UDP
service udp destination range 50000 51000
object network PABX
access-list outside_access_in extended permit object PABX-UDP any object-group PABX
nat (inside,outside) source static PABX 184.108.40.206 service PABX-UDP PABX-UDP
==> Replace 220.127.116.11 by your public ip or your object containing the public ip.
Afterwards, everything should work. Be sure to put the nat at the right place to not have something overlapping.
Do a test and let me know.
I saw in the title you were talking about udp range on ios.
You can use route-map or an easier one like below:
ip nat pool PABX-UDP 192.168.0.50 192.168.0.10 netmask 255.255.255.0 type rotary
access-list 111 permit udp any any range 50000 51000
ip nat inside destination list 111 pool PABX-UDP
You need to adapt with your actual config of any other Nat exists.
Here an example with route-map:
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