Australian businesses spent an average $159 a month on mobile phones and $102 on fixed lines over the past three years, according to a study of usage patterns released yesterday.
Voicemail retrieval was the most frequently called number by users, accounting for almost 14.5 percent of all telephone calls made.
And almost 20 percent of calls from corporate mobiles were made either on weekends or "out of hours" between 10pm and 4am, the study by the Full Circle Group found.
Anonymised data was collected from the group's software-as-a-service platform that connected to carrier billing systems and analysed raw call data to help businesses cut their telecommunications bills.
The study - which ran from January 2007 to July 2010 - covered 27,000 mobile phones, 10,000 fixed lines, and over $50 million in annual telecommunications spend, its creators said.
It surfaced an aggregated view of the telecommunications service usage patterns of businesses that showed the difficulty employers had enforcing policies around personal use of business devices.
"There is a crossover between business and consumer use [of a work-owned device]," managing director Tony Simmons said.
"How you [as a business owner] create that demarcation is a very hard thing to do."
Simmons conceded part of the difficulty in policing devices was the blurring of boundaries between work and home.
"The telcos see 7pm-to-7am as ‘out of hours' but we see a lot of [business] usage creeping over to 8 or 9 o'clock [at night]," Simmons said.
But he said there was "definitely a limit on weekends" to the calling patterns that businesses should tolerate.
"I see businesses with huge usage at 3am on a Sunday morning and text messages all across weekends," Simmons said.
"That can have really large cost implications [for businesses on corporate telecommunications plans]."
Business users spent an average 7.5 hours each month talking on mobile phones, the study found.
The average mobile-to-fixed line call was 161 seconds. Mobile-to-mobile calls were an average 134 seconds in length and "interfleet" calls - those made between company-owned fixed lines and mobiles - were an average 144 seconds.
The study found over 10 percent of call costs for businesses were interfleet - office-to-office, site-to-site, mobile-to-mobile, or mobile back to base.
Users left voicemails at an average length of 38 seconds.
"As voicemail is often charged in blocks of 30 seconds, this extra eight seconds has a cost consequence," the study said.
"Slightly shorter voice mails could shave four percent off mobile costs when voicemail is a chargeable item."
The study also questioned whether it was "fair" that carrier prompts increased the time needed for voicemail retrieval.
It said that "significant productivity gains" could be achieved if carriers offered a Voice2Text service, although Simmons acknowledged carriers that were able to charge for voicemail might be reticent to introduce other options.
"There are telcos that charge and don't charge for voicemail," he said. "The ones that charge for it want to protect that revenue- it's easy money."
Phone calls were most frequently made and received at 10am on Tuesday, Wednesday and Thursday ("implication: are clients trying to reach you and you are locked away in internal meetings", the study said).
Fixed costs stable
The decline in fixed line revenues reported by telcos such as Telstra was not as pronounced in the study results.
Monthly fixed line costs for each user had declined slightly over the three years of the study from $109 a month to $102 a month, although there had been a "big spike up in 2008", Simmons said.
The use of ISDN was also likely a factor in why the business sector had not contributed to the same fixed declines seen on copper PSTN services.
"An office might have ISDN 10 and... have up to 100 employees sitting off those 10 channels so you're going to find there's higher usage because the proportion of users per channel is going to be higher [than in the consumer world]," Simmons said.
Simmons said the Full Circle Group planned to release a further iteration of its study in six months, focusing on mobile data use.
He believed "things like iPads [were] going to transform office communications completely" in the future.