Sorry for the very long delay, this message just came up on my screen. These are the differences between the two, at least for the International data.
And how are the Adtrans connected to the PSTN?
Network switch, Cisco. Ancient model though. Sorry, I have to clock out here, I’ll be back on monday, but I’ll try to answer any questions if I see them on here before then.
The dial pattern for 8 (prefix) and 011XXXXXXX. (match pattern) appears to be defined the same way in both Adtran trunk groups. Like dicko asked, it is worth looking at how these Adtrans are connected to the PSTN. If it’s PRI-based service then on the Adtrans’ web interface you can usually go to Voice > System Setup > ISDN Num Templates, or Voice > System Setup > Dial Plan and see if this same international dial pattern is defined as needed.
So I have to manage international dialing from not only the PBX, but now I also have to connect to the Adtran’s directly to check any descrepency? I want to be sure that’s what has to be done here, since I’ve never directly logged into the Adtran before.
If the Adtran’s are going out via something like PRI then there might be some dial plan in place. Or not. But it’s a place to check. If your IP-PBX was just using regular ol’ Internet to connect to the provider then that’s one thing. But since the Adtrans are a layer between the IP-PBX and the PSTN then this is another component that might need a look.
The web interface is usually accessible via http://{the_adtran_IP} and usually the default username is admin and the default password is password.
You said that one phone was able to dial out internationally, while another one wasn’t, right? Remote into the other Adtran via the web interface and see what its dial plan looks like too.
How are the Adtrans getting to the PSTN? Via PRI?
The Adtran is the main thing that lets us dial out, yes.
I have an Adtran TA-924e at each larger site. Only for breaking out analog phone lines, however. But here is a dial plan that I have in place for them so that the connected clients can dial out and dial between extensions. No international for us, and the configuration is a bit different than your setup. But at least it shows a bit of configuration specifics. 
To reiterate, I would suggest posting a screen shot from your Adtran TA-908e’s dial plan. See if it looks like your other Adtran.
Like I said, without my directly knowing how exactly the Adtran is connecting out, it’s worth a shot. Save the changes, test, and if it doesn’t work then remove those lines you added. That’s worst case. Best case is it works!
For us, we don’t have any 7-digit dialing in our area. Since we got some new/split area codes. So I have full 10-digit dialing for local. Hence why my dial plan doesn’t list NXX-XXXX. But you can keep that entry on yours for local dialing, add NXX-NXX-XXXX for long distance dialing, and add the 011XXXXXXX$ for international dialing as give it a few test calls.
I can dial out to a london number (01144 20 7727 5486) [UK McDonalds], but attempting to dial out to the number our sales team needs to reach, yet again, it stops 5 [01197] digits in, and tells us “your call can’t be completed as dialed”. The Number that’s not working for anyone is in Dubai. The clients number is 12 digits long (minus the 011)
Last time you showed us that, the calls went out different Adtrans.
It’s not even hitting the PBX, it just goes 5 digits in and tells me it can’t dial out and goes busy with the ‘Reorder’
What doesn’t make any sense is that the number I dialed out to previously (011-971-2550-8607) gives me the same error, when it previously didn’t. Which makes no sense…
I’ve made a bit of progress when dialing out, but the one issue that’s been persisting is getting the system to even dial out. I’ve tried everything to get past the first 5 digits, but consistently, at least one international number gets stuck there and the system fires back the same error of ‘your call can not be completed as dials, please check the number and dial again’ with the “REORDER” error on the phone itself. I’ve looked in the PBX, the trunk, the Adtran units, I’m running out of areas to check here. If anyone here needs additional data, I can try and get it, but right now, I’m beyond lost…