The imp box uses caller ID information to screen your calls. This information is transmitted between the first and second rings on an incoming call. The imp silences the first ring, reads the caller ID, and then either passes the call on to your phone if it’s a Greenlist caller, takes a message if it’s a Greylist caller, or disconnects if it is a Redlist caller.
Some landline providers offer a Network answering service. Since the network is originating the call, it sees the first ring before imp silences it, but your landline phone does not. This means that the ring count now differs between the network and the landline phone by one (1) ring.
If you are using the imp in screening mode, and expecting Greenlist callers to still be able to leave a message on your landline, but you are finding that that is not happening as expected, it can be the result of a timing issue between the landline phone and the network.
For example, if you had your landline phone set to answer after 4 rings, and your network voicemail set to answer after 4 rings before the imp was installed, the landline answering machine would pick up after 4 rings, and the network answering machine would not take any message.
Now, with the imp installed, the network is seeing 4 rings, the imp box is ‘eating’ a ring, and the landline is seeing 3 rings. The network answering machine is picking up before the landline answering machine.
To correct this issue, contact your landline provider and increase the network answering machine ring count by at least one (1) ring.
If you’d like to try it on your own first, here are some quick links for answering machine setting troubleshooting for the most popular service providers:
Alternatively, you can decrease the number of rings on your home answering machine by one (1) ring.