OK...that is correct. This is straight from Cisco's page on the ATA:
Name Signaling Event based passthrough
Name Signaling Event (NSE)-based passthrough is simply thet transport of fax or modem communications using the G.711 codec.
The ATA 187 does not support NSE-based modem passthrough.
Also this...
Modem Standards
The ATA 187 supports the following modem standards:
•
V.90
•V.92
•V.44
•K56Flex
•ITU-T V.34 Annex 12
•ITU-T V.34
•V.32bis
•V.32
•V.21
•V.22
•V.23
Fax Services
The ATA 187 supports two modes of fax services, in which fax signals are transmitted using the G.711 codec:
•Fax pass-through mode—Receiver-side Called Station Identification (CED) tone detection with automatic G.711A-law or G.711µ-law switching.
•T.38 Fax Relay mode: The T.38 fax relay feature enables devices to use fax machines to send files over the IP network. In general, when a fax is received, it is converted to an image, sent to the T.38 fax device, and converted back to an analog fax signal. T.38 fax relays configured with voice gateways decode or demodulate the fax signals before they are transported over IP.
So with this, I would say to change your modem passthrough to an approved protocol listed above.
