| Business | Phone |
| Electronic Sound Co 691 39th St, Des Moines 50312 | (515) 274-3546 |
| Electronic Paging Products Inc 333 Sw 9th St F, Des Moines 50309 | (515) 284-7407 |
| Electronic Engineering Co 1015 Keosauqua Way, Des Moines 50309 | (515) 283-1100 |
| Heartland Communications 1015 Keo Way, Des Moines 50309 | (515) 362-3145 |
| Iowa Phone Systems Des Moines 50309 | (515) 309-1480 |