bubblestar

Theorectically yes, I think.  

Instead of using VoIP2 in PSTN Tab, you may turn the direction to VoIP1 in Line 1 Tab in where we have another 4 gateway accounts from Gateway1 to Gateway4.

I haven't tried to test but I think the logic is same.

I am successfully using the similar method to initiate PSTN call thru remote VoIP2 of SPA3102 via HTTP Digest.  The trick is to register a new trunk in Asterisk Server as usual with your desired ET2x3 in one of the 4 Gateway accounts.

In my case, the trunk is not really registered but it can still be connected. YHFung also successfull makes use of this HTTP Digest method to use other remote PSTN land line.

Of course, in your case, I understand that you just want to use VoIP Gateway instead of PSTN Gateway.  So that why I ask you to try the 4 extra VoIP Gateways in Line 1 instead of PSTN Line.

You may refer to tamtsin C-hing's manual on page 6 of his Admin Guide to set up the Gateway first and then establish a trunk in your Asterisk Server to achieve it.  Hope you can succeed and please share if you can manage to do it.

bubblestar

非常同意。

以前用一般方法設定PSTN-To-VoIP 或 VoIP-To-PSTN 時，經常接不到所要的線路，特別是加了PIN之後，問題好大機會是出自DTMF的辨識成功率非常低。但用了HTTP Digest 的方法之後，接入接出都很好。

bubblestar

Sorry for the confusion.  

I've just taken HTTP Digest as an example to explain how we can establish a trunk in Asterisk to use the PSTN landline in remote ATA without using the regular subscriber account in PSTN Tab.

I think you can do similar settings by registering ET263 in one of the 4 Gateway Accounts in Line1 first.  Then, establish a trunk as usual in Asterisk to dial out via these gateway accounts in the remote end to reach the target party.

The point is that we don't use the Regular Subcriber Accounts in Line1 to initiate calls.  We use the extra 4 GATEWAY Accounts.  This is the unique function on SPA3000 or SPA3102.