Nortel T1/SMDI Configuration Manual page 173

February 2008
CallPilot SMDI link RS-232 physical link
In its simplest form, the CallPilot SMDI link connects directly to external
terminating equipment using an RS-232 physical link for the entire
transmission medium.
The following illustration shows the inclusion of a null modem in the
RS-232 path. A null modem is required whenever (usually) the RS-232
interface on the terminating switch equipment is of type DTE, so that RS-
232 equipment at each end does not attempt to transmit on the same signals
of the RS-232 link. Alternatively, if the terminating RS-232 equipment is of
type DCE, the null modem must not be used.
RS-232 Physical link
Switch
As indicated in Reference Number 1, referred to on page 188, the SMDI
protocol can be carried on an RS-232 physical link. SMDI formatted
messages are composed simply of strings of ASCII characters, which are
conveyed from one end of the RS-232 link to the other in serial data
transmission format.
The RS-232 protocol is defined in Reference Number 2 on page 188;
however, note that the protocol does not include any definition of or
reference to the SMDI protocol.
T1/SMDI and CallPilot Server Configuration
User-supplied null modem required
whenever connecting to another DTE
(that is, no-handshaking version)
D
T
E
Network-engineered,
user-supplied RS-232
physical link cables
(carries SMDI protocol
messages)
CallPilot T1/SMDI interfaces
DB-9
CallPilot
(female)
server
DTE
DB-25
(male)
CallPilot RS-232 link
demarcation point
g250068
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