COM Enumerator Recognition by Modems
Hayes modems and Terminal Adapters (TAs) follow the sample implementation
given in Plug and Play External COM Device Draft Specification, Rev. 1.00
for modems clarified in the following information:
1. While off-hook, Hayes modems ignore DTR/RTS enumeration probes (defined
in Plug and Play External COM Device Draft Specification, Rev. 1.00).
2. While on-hook, Hayes modems respond to DTR/RTS enumeration probes by
sending their SPNP ID sequence as defined below:
- Except for &D3, the modem settings for &Dn, and &Rn do
not affect the detection of the DTR/RTS enumeration probes.
3. The &Sn setting may affect SPNP when DSR=0, the DTE may be inhibited
from sending the SPNP DTR/RTS probe.
4. In &D3 mode, Hayes modems are not required to respond to the enumerator
probe (because they perform a hardware reset when DTR goes off).
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