这是官方论坛里面关于保号的说明：
Keep your number before it's removed
If you don't want to lose your number, do one of the following before the reclaim date:
- Make a call or answer a call with your Voice number
- Send a text message with your Voice number
- Listen to your voicemail
- Open the Voice app on your mobile device
If you don't want to lose your number, do one of the following before the reclaim date:
- Make a call or answer a call with your Voice number
- Send a text message with your Voice number
- Listen to your voicemail
- Open the Voice app on your mobile device
- 参考：https://support.google.com/voice/answer/159519?hl=en
- 记得之前第二条包含接受短信，但是现在没说接受短信能保号了。
- 第四条待测，毕竟之前的官方条款都能过期不更新！
所以稳妥点还是经常给频道内号码发个短信（打电话可能影响到别人，而且不知道打不通的情况算不算是上述第一条说的make a call）交流交流！