Northern Telecom yesterday made its pitch for the large-scale private network market with a set of Integrated Services Digital Networking tools and facilities to go with its Meridian SL family of PABXs. The products, bundled together as Meridian Customer-Defined Networking, include features previously only available from telephone companies such as caller identification, call screening, call forwarding and tracing. Northern Telecom doesn’t want to market the system direct, preferring to sign large-scale systems implementors, and says it is close to an agreement for General Motors Corp’s Electronic Data Systems to be the first to market the suite of products. It also hopes to interest some or all of the Bell regional operating companies in marketing the facilities. A faster processor for the Meridian SL exchange was also announced, but no further details were available.