The Telecom division leveraged the 1603 processor into the heart of its original CBX. Over time, the company began to focus on digital voice, and produced some of the earliest examples of all-digital voice equipment, including Computerized Branch Exchanges (CBXs) and digital phones. Two of the most popular telecom systems were the ROLM CBX and ROLM Redwood (PBX and Key Systems Unit (KSU) models, respectively). The CBX was meant to directly compete with Northern Telecom's SL-1, AT&T Dimension telephone systems and other computerized digital-voice systems being developed at the time. By 1980, ROLM had shot past AT&T in number of systems deployed to become the #2 PBX in North America. The Redwood, often called the "Deadwood" by many ROLM techs because it never caught on, was intended to compete with the Nortel Norstar Key System. When Siemens bought ROLM from IBM and introduced their "newer" models, which were renamed Siemens switches, the early ROLM phone switches were widely pressed into service as old technology (though a number of 8000 and 9751-9005 CBXs remain online at some companies), but the digital phone handsets were quite valuable for those expanding their phone networks. The later ROLM 9200 (actually a Siemens HCM200 Hybrid system renamed) was more competition for the leading Key Systems as the 9200 had intensive Least Call Routing software, which the Redwood did not. The company also produced one of the first commercially successful voicemail systems, PhoneMail. Digital ROLM telephones, called ROLMphones, were unique from other telephones in many ways, one of which was a lack of a physical switchhook button. Instead, the handset contains a small magnet which triggers a switch in the phone base. The opening or closing of this switch lets the phone and system know if the phone is on hook (not in use) or off-hook (in use).
