I need to list all available ports (left join) in subform?

[dca]

I am working on a database to keep track of the devices in my SAN. Currently I have the following schema

Table KeyFields
SwitchInfo
ID (SwitchID)
ModelID
ModelInfo
ID (ModelID)
ModelMap
ID (MapID)
ModelID
Connections
SwitchID
MapID

I have a SwitchInfo form which has a connections subform. I would like to list all possible ports from the ModelMap table in this subform and the connection information. I tried using a query that joins the ModelMap and Connections but it would not allow a left join. I then tried to use the wizard and added the table fields directly to the subform. This only listed one line and when I added a record it added a record to the ModelMap table which I want to remain a static list of ports for each model of switch. When I add a connection for a port specified in the map I want to update the Connections table with the mapid key and the other fields in the connection table without changing the ModelMap table.