josef@nixpbe.UUCP (Moellers) (09/27/90)
Hi, I recently started to take a closer look at the interfaces between the ISO layers. In particular, I looked at ISO DIS 10022, which describes the interface between the physical layer (Layer 1) and the data link layer (Layer 2). ISO DIS 10022 describes three "Physical Service primitives": - Ph-ACTIVATE request/indication - Ph-DATA request/indication - Ph-DEACTIVATE request/indication. I have a question concerning connection establishment, i.e. a Ph-ACTIVATE request: ISO DIS 10022 sais that with a Ph-ACTIVATE request, "Parameters associated with the class of service are for further study", but refers only to such things as - Type of transmission (synchronous and asynchronous), - Mode of operation (duplex, half-duplex, and simplex), and - Topology (point-to-point and multi-endpoint). If I have a dial-up line, e.g. a V.24 (RS232) connection with a V25bis modem or an X.21 connection, the connection establishment phase in each of these two configurations is somewhat different to the data transfer phase, how would one specify things like - type of transmission while dialling (in V.25bis one could dial synchronous and then transfer asynchronous) - what "number" to dial? PLEASE no answers like "You would never use this interface explicitly"! Thanks, -- | Josef Moellers | c/o Nixdorf Computer AG | | USA: mollers.pad@nixdorf.com | Abt. PXD-S14 | | !USA: mollers.pad@nixdorf.de | Heinz-Nixdorf-Ring | | Phone: (+49) 5251 104662 | D-4790 Paderborn |